HomeMy WebLinkAboutTroy & Kristi Rough Draft 8-8-2022
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1.0 INTRODUCTION
1.01 SCOPE:
1. This volume, entitled UNIFORM DEVELOPMENT DESIGN MANUAL sets forth the minimum
acceptable criteria for public and private facilities and parking lots within the City of Twin
Falls. Deviations or variances from these standards, may be considered; however, it shall be
the responsibility of the applicant to demonstrate to the satisfaction of the City Engineer
the proposed variance meets or exceeds the minimum acceptable criteria. Any proposed
waiver of a City Code provision may only be made according to the procedures set forth in
the City Code. Policies and technical criteria not specifically addressed in this document
shall follow the provisions of the latest editions, or as noted in this manual, the Idaho
Standards for Public Works Construction, City revisions thereof, AASHTO or MUTCD
standards.
2. The purpose of this manual is to establish minimum requirements for design, plans,
construction, testing, inspection, and supporting documents for the City of Twin Falls herein
referred to as the “City”. This Manual incorporates the City of Twin Falls’ Revisions to the
Idaho Standards for Public Works Construction (City Standards). The requirements herein,
unless otherwise noted, apply to public and private improvements. This includes, but is not
limited to, Public Works Projects, Subdivisions, Special Use Permits, Conditional Use Permit,
Site Plan Review, Zone Changes, Annexations, Floodplain, or Building Permits.
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1.02 AUTHORITY:
1.02.1 Laws, Ordinances and Specifications
1. The Contractor is assumed to be familiar with all federal, state, and local laws, ordinances,
regulations, and standards, which, in any manner, affect those engaged or employed in the
work or the materials or the equipment used in the proposed construction or which in any
way affect the quality of the work.
2. No plea of misunderstanding will be considered because of alleged ignorance thereof.
a. If the contractor discovers any provision in the plans, specifications or contract which is
contrary to or inconsistent with any law, ordinance, regulation or standard, he/she shall
forthwith report it to the City.
1.02.2 Authority of City
1. It is understood and agreed that the work being performed is to be done in accordance with
the approved plans and specifications and to the satisfaction of the City.
a. The City may appoint an assistant and/or inspector to inspect the materials used and the
work performed.
2. The City may make periodic visits to the site of the project to observe the progress and
quality of the work and to determine if the work is proceeding in accordance with the
submitted plans, City Standards, and other requirements of this Manual.
a. The City will not make comprehensive or continuous construction reviews to check quality
of the work and compliance with the plans and specifications.
b. The City is not responsible for construction means, methods, techniques, sequences, or
procedures or for safety precautions and programs in connection with the work.
3. Visits and observations made by the City shall not relieve the Contractor of their obligation
to conduct comprehensive inspections of the work, to furnish materials and perform
acceptable work, and to provide adequate safety precautions in conformance with the
intent of the contract. The fact that a Contractor's error goes undetected during a
construction review by the City does not relieve the Contractor of the responsibility or the
discovery of his own errors and the correction of them or of the responsibility for properly
performing the work.
4. The approval by the City of any drawings or any method of work proposed by the
Contractor shall not relieve the Contractor of any responsibility for any errors therein and
shall not be regarded as any assumption of risk or liability by the City or any officer or
employee thereof. The Contractor shall have no claim on account of the failure or partial
failure or inefficiency of any plan or methods approved. Such approval shall be considered
to mean merely that the City has no objection to the Contractor's using, upon the
Contractor’s full responsibility, the plans or methods proposed.
1.02.3 City’s Representatives
1. The City may appoint representatives to inspect all materials used and all work done by the
Contractor. Such inspections may extend to any part or all of the work and to the
preparation or manufacture of the materials to be used.
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2. The representatives will not be authorized to revoke, alter, enlarge, relax, or revise any City
Standards or other requirements of this Manual or the approved plans. The representative’s
role is to keep the City informed as to the progress of the work and the manner in which it is
being done, and to call to the attention of the Contractor any deviations from the plans or
specifications. Failure of the representative to call the attention of the Contractor to faulty
work or infringement upon the requirements of the plans or specifications shall not
constitute acceptance of said work.
3. The representative will not be authorized to approve or accept any portion of the work or
to issue instructions contrary to plans and specifications approved by the City in writing.
4. The representative will have the authority to reject defective material and to suspend any
work that is being improperly installed or constructed, subject to the final decision of the
City Engineer. The representative will exercise such additional authority as may, from time
to time, be especially delegated to him by the City Engineer.
1.02.4 Administrative Competence
1. The Contractor shall be supplied with plans that have been approved by the City and other
necessary jurisdiction approvals. The Contractor shall have a competent superintendent on
the project at all times (regardless of the amount of subcontracted work). The
superintendent must be capable of reading and thoroughly understanding the plans and
specifications, and thoroughly experienced in the type of work being performed.
1.02.5 Verbal Agreements
1. No verbal agreement or conversation with any officer, agent, or employee of the City,
either before or after execution of the project, shall affect or modify any of the terms or
obligations contained in these Standards. Any such verbal communication shall be
considered as unofficial information and shall in no way be binding upon the City.
1.03 REVISION:
1. Revisions to this Uniform Development Design Manual may be adopted annually and as
often as needed. It is the responsibility of the Consultant/Contractor/Developer to obtain
the latest revisions from the City.
2. The contractor is encouraged to check the City of Twin Falls Website for the latest revision
to the design manual and have a copy available on the job site.
1.04 REVIEW AND APPROVAL:
1. City Staff will review all submittals for general compliance with these Specifications.
However, approval by the City does not relieve the owner, engineer, or designer from the
responsibility of ensuring their calculations, plans, specifications, construction and as-built
drawings are correct and in compliance with these Design and Construction Standards.
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1.05 INTERPRETATIONS:
1. In the interpretation and application of the provisions of the Design Manual, the following
shall govern:
a. These Standards shall be regarded as the minimum requirements needed for the
protection of health, safety, and welfare of the people of Twin Falls, and shall be liberally
construed to further such purposes.
b. Whenever these Standards and any law, ordinance, resolution, rule, or regulation of any
kind contain any restrictions covering any of the same subject matter, whichever
standards produce higher quality shall govern.
c. These Standards shall not abrogate or annul any permits issued before their effective date;
any construction plans approved before their effective date; or any final plat documents
that have been recommended for approval by the Planning Commission prior to effective
date of these Standards.
d. Any interpretation of this manual shall be performed by the City Engineer.
1.06 REFERENCES:
1.01.1 This Manual refers to, and is to be used in conjunction with, the Idaho Standard for Public
Works Construction and the City of Twin Falls revisions thereto using the latest adopted
edition. Additional design publications referenced herein include, but are not limited to, the
following standards and specifications (the more restrictive requirements shall apply), where
applicable:
A Policy on Geometric Designs of Highways, American Association of State Highway and
Transportation Officials (AASHTO)
American National Standards Institute (ANSI)
American Water Works Association (AWWA) Standards
FIRM Flood Insurance Rate Map, Federal Emergency Management Agency
Guidelines for Development of New Bicycle Facilities, (AASHTO)
Guidelines for Urban Major Street Design, Institute of Traffic Engineers (ITE)
Idaho Standards for Public Works Construction (ISPWC) When referenced below, it is for the
current adopted standard and includes the City of Twin Falls revisions to the ISPWC
Idaho Transportation Department “Standard Specification for Highway Construction”
Manual on Uniform Traffic Control Devices (MUTCD), Federal Highway Administration
National Fire Protection Association Code (NFPA)
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State of Idaho Regulations for Public Drinking Water Systems (IDAPA)
City of Twin Falls Wastewater Collection System Master Plan
City of Twin Falls Master Transportation Plan
City of Twin Falls Stormwater Management Plan (when adopted)
City of Twin Falls Pressure Irrigation Master Plan
City of Twin Falls Water System Master Plan
Idaho Standards for Public Works Construction Field QC Manual
Roadside Design Guide (AASHTO)
1.07 ABBREVIATIONS:
1.07.1 Whenever the following abbreviations are used in the contract documents and/or plans, the
abbreviations are to be construed the same as the respective expressions represented
hereinafter:
AASHTO: American Association of State Highway and Transportation Officials
ADA: Americans with Disabilities Act of 1990, a Federal law
AADT: Average Annual Daily Traffic
ADT: Average Daily Traffic
ANSI: American National Standards Institute
ASA: American Standards Association
ASSE: American Society of Sanitary Engineers
ASTM: American Society for Testing and Materials
AWWA: American Water Works Association
CIP: Capital Improvements Plan
COTF: City of Twin Falls
DEQ: Department of Environmental Quality
DOT: United States Department of Transportation
EPA: Environmental Protection Agency
FHWA: Federal Highway Administration
IDAPA: Idaho Administrative Procedures Act
ITD: Idaho Transportation Department
IDWR: Idaho Department of Water Resources
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LHTAC: Local Highway Technical Assistance Council
ISPWC: Idaho Standards for Public Works Construction
LOS: Level of Service
MPO: Metropolitan Planning Organizations
SCPHD: South Central Public Health District
TFHD: Twin Falls Highway District
UDC: Uniform Development Code
USB: Urban Service Boundary also known as water service boundary
URA: Urban Renewal Agency
1.08 DEFINITIONS:
1.08.1 The following words and phrases, when used in this manual, shall have the meanings
respectively ascribed to them as follows. Any term used herein that is not defined shall follow
definition outlined in City Code Title 10:
Accessibility: The extent to which facilities are usable by people with disabilities, including
wheelchair hearing, and vision impaired users.
Addition (to an existing building): An extension or increase in the floor area or height of a
building or structure.
Appeal: A request for review of the interpretation of provisions of this ordinance or request
for a variance.
Average Daily Traffic: An estimate or statistical value of traffic volume based on actual
traffic counts, or counts generated by an acceptable software model, using a particular
street or intersection that is adjusted to account for typical day of the week and month of
the year variations. This term is also sometimes used to express the estimated daily trip
generation for a particular land development.
Bedding: The area of Pipe Zone located below the haunching of the pipe.
Bicycle Facilities: A general term denoting improvements and/or provisions made by public
agencies to accommodate or encourage bicycling, including parking facilities, mapping all
bikeways, and shared roadways not specifically signed or designated for bicycle use.
Bicycle Lane (Bike Lane): A portion of a roadway which has been designated by striping,
signing and pavement markings for the preferential or exclusive use of bicyclists.
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Bicycle Path (Bike Path): A bikeway physically separated from motorized vehicular traffic by
an open space or barrier and either within the highway right‐of‐way or within an easement.
Bicycle Route (Bike Route): A segment of a system of bikeways designated by the
jurisdiction having authority with appropriate directional and informational markers, with
or without specific bicycle route number.
Bikeway: Any road, path or route which in some manner is specifically designated as being
open to bicycle travel, regardless of whether such facilities are designated for the exclusive
use of bicycles or are to be shared with other transportation modes.
BMPs: Best Management Practices: A BMP is a procedure, technique, or structure used to
reduce the pollutant content of storm water discharge from a specific location.
Building Permit: The development permit issued by the City before any building or
construction activity can be initiated on a lot, tract, or parcel of land.
Capacity (Traffic): The maximum number of vehicles which have a reasonable expectation
of passing over a given section of a street in one direction, or in both directions of a
highway, during a given time period, under prevailing traffic conditions, expressed in terms
of vehicles per hour or maximum critical turn volumes each of which is described under
Level of Service. Capacity is typically measured in the PM Peak Hour.
City Attorney: The official charged with the title of City Attorney of the City of Twin Falls,
and/or their designee whose function is to advise and represent the City in legal matters.
City Engineer: The official charged with the title of City Engineer of the City of Twin Falls,
and/or their designee.
City of Twin Falls Municipal Code: A codified collection of laws enacted by the Twin Falls
City Council.
City Standards: (See Twin Falls Revisions)
City: The City of Twin Falls. The authorized representative of the City of Twin Falls dealing
with matters in the City’s Right-of- Way shall be the City Engineer and any other City
employees as designated by the City Engineer.
Code: An article of the Twin Falls Municipal Code together with related adopted documents.
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Comprehensive Plan: A comprehensive, long‐term general plan for the physical
development of the City.
Construction Standards: See ISPWC and Twin Falls Revisions.
Contractor: The term Contractor means any individual or entity that performs Work within
the Right- of-Way or public easements including but not limited to: Contractors, Sub-
Contractors, Developer(s), Owner(s), Owners’ Agents, Utility Companies, and/or City Crews.
Datum: The vertical datum is a base measurement point (or set of points) from which all
elevations are determined. Historically, that common set of points was the National
Geodetic Vertical Datum of 1929 (NGVD29). The vertical datum currently adopted by the
federal government and the City of Twin Falls as a basis for measuring heights is the North
American Vertical Datum of 1988 (NAVD88).
Default: The improvements listed in the improvement agreement have not been completed
by the subdivider/developer within the period concurred to by the City Council including
any applicable extensions in time, and/or the security posted by the subdivider/developer
to ensure that improvements will be completed, has lapsed, or been revoked by the surety.
Developer: Individual or entity with ownership and/or operational control of the
development of the public infrastructure and improvements associated with a subdivision
and/or development.
Development: Any man-made change to improved or unimproved real estate, including but
not limited to buildings or other structures, mining, dredging, filling, grading, paving,
excavation or drilling operations, or storage of equipment or materials.
Discharge Point: A point or location where surface or storm water runoff is concentrated
before being released from the property.
Drainage Area: Consists of the entire catchment area which contributes surface and storm
water runoff to a specific point.
Drainage Fixture Units (DFU): A measure of the probable discharge into the drainage
system by various types of plumbing fixtures. The measure is expressed in units of cubic
volume per minute. The value for a particular fixture depends on the volume rate of
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drainage discharge, the time duration of a single drainage operation, and the average time
between successive operations.
Drainage Way: An open linear depression, whether constructed or natural, which functions
for the collection and drainage of surface water. It may be permanently or temporarily
inundated and may or may not contain aquatic vegetation or aquatic life.
Drawings or Plans: The official drawings, plans, profiles, typical cross‐sections, and shop
drawings (or reproductions thereof) approved or issued by the City that show the location,
character, dimension, and details of the work to be performed.
Driveway – Shared: A driveway serving more than one property.
Driveway Approach: That portion of a driveway where it abuts a public way and the
property line.
Driveway: An area that provides vehicular access to a site, except for public and private
streets and alleys. A driveway begins at the property line and extends into the site.
Driveways do not include parking, maneuvering, or circulation areas in parking lots, or
parking spaces.
Easement: Aright of use, falling short of ownership, and usually granted for a certain stated
use or uses.
Emergency Overflow: A waterway in or about a hydraulic structure which allows the release
of excess water.
Encroachment: The advance or infringement of uses; fill, excavation, buildings, structures,
or development into a floodplain, adjoining property, or right-of-way.
Engineer of Record: Any person retained as a consultant by the owner/developer and is
legally authorized to practice professional engineering in the State of Idaho in accordance
with the Laws of Idaho, having especially qualified in specific discipline.
Engineer: Any person retained as a consultant by the owner/developer and is legally
authorized to practice professional engineering in the State of Idaho in accordance with the
Laws of Idaho, having especially qualified in specific discipline.
Engineered Plans: Plans, profiles, cross sections, calculations, and other required details for
the construction of public or private improvements, prepared by a professional engineer
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licensed by the state of Idaho and in current standing, in accordance and in compliance with
existing standards of design and construction approval.
Erosion Control: Control the unwanted movement of soil
Commented \[TV1\]: Look this up with SWPPP plan
terminology. Methods by which you control the unwanted
Estimated Quantities: The Estimated Quantities are based on improvements for the site
movement of soil
plan, landscaping, utilities, etc. (This estimate does not include the building.)
Expansion of Street Capacity: Any widening, intersection improvement, signalization or
other capital improvement designed to increase the existing street's capacity to carry
vehicles.
Expressions: Wherever the words, “as directed”, “as required”, “as permitted”, or words of
like meaning are used, it shall be understood that the direction, requirements, or
permission of the City Engineer or designee is intended. Similarly, the words “approved”,
“acceptable”, “satisfactory” shall refer to approval by the City Engineer or designee.
Whenever the words “these Specifications” are used it shall be understood that reference is
made to the City of Twin Falls “Design Manual” and “Idaho Standards for Public Works
Construction Standards (ISPWC)” and City of Twin Falls revisions to ISPWC including all
parts, supplements, and revisions pertaining thereto.
Fats, Oils, and Grease (FOG): Organic polar compounds derived from animal and/or plant
sources. These oils are used in, or a byproduct of, the cooking or food preparation process.
The oils turn or may turn viscous or may solidify with a change in temperature or other
condition.
Final Acceptance: Upon completion of the entire project, after the one‐year warranty
period has elapsed, and when all deficiencies have been corrected to the City’s satisfaction.
Fire Chief: That official charged with the title of Fire Chief of the City of Twin Falls, and/or
their designee.
Floodway: See definition in Title 10
Force Main: A pressurized sanitary sewer line, which conveys sewage from a pumping
station to a higher elevation in the sewer from which gravity flow may resume.
Freeboard: See definition in Title 10
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Formatted: Font: 12 pt, Highlight
Gravity Irrigation Supply Ditch: A ditch conveying water for irrigation or agricultural
purposes that is owned and/or controlled by a ditch or utility company.
Groundwater: Concentrated water beneath the earth’s surface.
Historic Flow: The runoff which has historically flowed off from the property in question for
the specified storm frequency and duration prior to development. This would be either the
land’s pre- development agricultural (to be calculated as grass pasture in good condition) or
native condition.
Historic Structure: A structure that is:
1. Listed individually in the National Register of Historic Places (a listing maintained by the U.S.
Department of Interior) or preliminarily determined by the Secretary of the Interior as
meeting the requirements for individual listing on the National Register:
a. Contributing Historic Structure
b. Non-Contributing Historic Structure
2. Certified or preliminarily determined by the Secretary of the Interior as contributing to the
historical significance of a registered historic district or to a district preliminarily determined
by the Secretary to qualify as a registered historic district.
3. Individually listed on a state inventory of historic places and determined as eligible by states
with historic preservation programs which have been approved by the Secretary of the
Interior, or
4. Individually listed on a local inventory of historic places and determined as eligible by
communities with historic preservation programs that have been certified either:
a. By an approved state program as determined by the Secretary of the Interior, or
b. Directly by the Secretary of the Interior in states without approved programs.
Improvement Agreement: An agreement executed between the City of Twin Falls and the
owner of land to be subdivided or developed and where public improvements are to be
Commented \[TV2\]: Move down
installed, modified, or removed.
Improvement Plans: The plans, profiles, cross‐sections and drawings or reproductions
thereof, prepared by a registered professional engineer, which show the details of the work
to be done on improvements.
Inspector: An authorized representative of the City assigned to inspect the work performed
(or being performed) and the materials furnished (or being furnished) by the Contractor.
Interceptor: A pipe having a minimum inside diameter of 18 inches which conveys sewage
and feeds by gravity to a publicly owned and maintained wastewater treatment plant.
Commented \[TV3\]: Interceptor the right term?
Trunkline?
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International Building Code (IBC): is a model building code developed by the International
Code Council (ICC). It has been adopted for use as a base code standard in the City of Twin
Falls.
International Plumbing Code (IPC): is a model plumbing code developed by the
International Code Council (ICC). It has been adopted for use as a base code standard in the
City of Twin Falls.
Level of Service: A qualitative measure describing operational conditions from "Level A"
(best‐ represents unimpeded flow) to "Level F" (worst‐represents a highly impeded, packed
condition), within a traffic stream or at intersections.
Lot/ Parcel: A unit of land lawfully created by a recorded subdivision plat, any distinct
parcel, or any portion of real property divided with the intent of transfer of ownership or
for building development.
Mechanical Stabilization: The application or use of structural measures such as rock rip‐rap,
gabions, Turfstone or an approved equal, to provide sufficient soil cover to prevent soil
movement by action of wind, water, or structure loading. Stabilization may include
incorporation of approved vegetative measures so that, in combination, the structural and
vegetative measures will provide an appropriate level of protection. The City Engineer will
determine whether the proposed methods are appropriate.
Metropolitan Planning Organization (MPO): A planning agency consisting of a board
representing the county and each incorporated city. The role of the MPO is to coordinate
planning activities within the county. The MPO is a transportation policymaking and
Commented \[TV4\]: Change definition. Find some other
MPO info
planning body with representatives of local, state, and federal government and
transportation authorities. The members of the MPO can consist of elected officials, state
agencies, interest groups, private sectors, federal agencies, transit operators, general
public, and local government agencies. The MPO provides local elected officials input into
the planning and implementation of federal transportation funds within the designated
urban area. The MPO provides policymaking, planning, coordination, and collaboration for
the area transportation and ensures that a comprehensive, cooperative, and continuing
process is used to ensure federal spending on transportation related projects.
Commented \[EAG5\]: Directly from the 2022 TMP. I don’t
know if this is a better definition.
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Multi-Use Pathway: A paved way (typically 10 to 12 feet wide) that is physically separated
from motorized vehicular traffic; typically shared with pedestrians, bicyclists, and other
non-motorized users.
Natural Drainage Channel: Drainage structures which occur naturally prior to any manmade
disturbance which could convey storm water to a creek, canal, or stream.
Natural Watercourse: A natural creek, stream, or river, whether seasonal, intermittent, or
perpetually flowing.
Observer: The authorized representative of the Project Manager assigned to observe the
work.
Or Equal: In order to establish a basis of quality, certain processes, types of machinery and
equipment or kinds of materials may be mentioned by designating a manufacturer and/or
referring to specific brand or model numbers. Such reference is not intended to exclude
other processes, equipment or materials that will meet the designated standards of the
particular product specified. If the Contractor desires to use other products as equal to that
indicated or specified, they shall first secure the approval of the City before entering an
order. Wherever the specifications reference a manufacturer's name, brand, or model, it is
understood that the phrase "or equal" is assumed to follow thereafter whether, in fact, it
does or does not.
Ordinance: A law or decree enacted by the Twin Falls City Council.
OSHA: Occupational Safety & Health Administration
Owner: The person, persons or other legal entity holding legal title by deed to land, or
holding legal title as vendees under land contract, or holding any other legal title of record.
Panel: Any section defined by joints, score marks, or an approximate square when joints do
not exist.
Peak Flow: Maximum rate of storm water runoff at a point under investigation
Pipe Zone: The zone in a backfilling operation which provides support and surrounds the
pipe barrel. The zone extents are typically set by the pipe manufacture.
Planning & Zoning Director: That official charged with the title of Planning & Zoning
Director of the City of Twin Falls, and/or their designee.
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PM Peak Hour traffic volumes: The highest traffic volumes during four consecutive 15-
minute periods usually between the hours of 4:00 PM and 6:00 PM.
Project Manager: The authorized representative of the City who provides overall technical
coordination and monitoring of work. However, for private projects the term shall be
synonymous with Public Improvement Inspector.
Project: All work to be performed by the Contractor, including the furnishing of all material,
equipment, labor, tools, and incidentals required to complete the work.
Public Works Director: That official charged with the title of Public Works Director of the
City of Twin Falls, and/or their designee.
Record Drawings: Plans accepted by the City as the official plans of the subdivision,
development or project which contain public infrastructure and are placed on file with the
City.
Right-of-Way: The City of Twin Falls’ Public Right-of-Way. This includes but is not limited to
public streets, curbs, gutters, sidewalks, and other areas owned or maintained by the City of
Twin Falls. Records of ownership are kept at the Twin Falls County Recorder’s Office.
Roughness Coefficient: Value used in Manning’s equation to estimate a material’s
resistance to the flow of water. Usually represented as “n”.
Runoff Coefficient: Value used in the Rational Method to estimate the permeability of
ground cover to water runoff.
Security: A notarized letter of credit furnished by a bank or financial institution authorized
to do business in the State of Idaho, in the form approved by the City Attorney; or in lieu
thereof, a cashier’s check or a certified check of the subdivider/developer made payable to
the City of Twin Falls, or a cash deposit with the City in lawful money of the government of
the United States, provided further than under no circumstances shall the word be
construed to authorize or permit a personal bond or other security other than that
described herein. The City of Twin Falls requires bond values to be developed by the
Engineer of Record, confirmed by the City of Twin Falls to be valued at historical values that
the City has paid and include 20% for overhead.
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Sewer Main: A sanitary sewer constructed within public right‐of‐way which transports
sewage to an interceptor sanitary sewer. Sewer Mains shall start and end with a structure.
Commented \[TV6\]: Add definition for substantial
completion
Shared Use Path: Any path, or route which in some manner is specifically designated as
being open to pedestrian and/or bicycle travel, regardless of whether such facilities are
designated for the exclusive use of bicycles or are to be shared with other transportation
modes.
Sheet Flow: A shallow mass of storm water runoff in the upper reaches of a sub-basin.
Sidewalk: A public pedestrian walkway located adjacent to or immediately near a street
Formatted: Font: 12 pt
designated for the movement of pedestrians and meeting the requirements of the Federal
Americans with Disabilities Act.
Stable Rock: means a rock slope as certified by an Idaho licensed engineer that will stand
near vertical and provide perpetuity and stability against weathering.
Standard Revisions/Specifications: See Twin Falls Revisions to ISPWC.
Storm Water Facility: A detention and/or retention pond, swale, drywell, or other surface
water feature that provides storage during high‐rainfall events and/or water quality
treatment.
Storm Water Pollution Prevention Plan: Drawing which represents the Best Management
Practices used in preventing polluted storm water from leaving the site.
Storm Water Runoff: Water resulting from precipitation running off the surface of a
drainage area during or immediately following a storm event.
Stormwater Detention Facility: The facility used to store storm water runoff for controlled
Commented \[TV7\]: Change to Stormwater – Detention
and move down
release during and/or following a storm event.
Stormwater Retention: The facility used to store storm water runoff during and/or
following a storm event to be released through infiltration or evaporation and not released
into drainageways or other storm systems.
Street Designation: The categorization of a street as local, minor collector, major collector,
arterial, etc., based on the average daily traffic (ADT) at ultimate buildout and/or Master
Transportation Plan functional classification.
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Street Superintendent: That official charged with the title of Street Superintendent of the
City of Twin Falls, and/or their designee.
Street‐Private: A street which is to be owned and maintained by parties other than the City
or other government agency. Not allowed when serving more than 4 lots.
Street A street owned by the City or other government agency.
Structure: See definition in Title 10
Subdivider: See definition in Title 10
Subdivision: See definition in Title 10
Substantial Completion: Add Definition
Commented \[EAG8\]: Add definition for substantial
completion
Surety: The entity which bonds and guarantees the Contractor’s satisfactory performance
of the work as described in these standards. (Bonded)
Surveyor: A person who is retained by the owner/developer and is currently licensed to
practice land surveying in the State of Idaho in accordance with the Laws of Idaho.
Temporary Work: A period of time not to exceed 6 months.
Commented \[TV9\]: Do we need this?
Testing Agency: Any individual or other person or entity which is qualified and licensed to
perform the required sampling, analysis, testing, and professional recommendation service.
Time of Concentration: The time it takes a drop of water falling on the hydraulically most
remote point in the watershed to travel through the watershed to the outlet.
Topographical Constraint: Where existing slopes, wetlands, water bodies, rock
outcroppings, or other physical features of a site, which are not caused or created by the
applicant or their agents, prevent conformance with the design standard.
Traffic Calming: The combination of mainly physical measures that reduce speeds and/or
volumes of motor vehicles on a roadway with calming features which alters driver behavior
and improves conditions for non‐motorized street users.
Trip Generation: The attraction or production of trips caused by a certain type of land
development.
Trip: A one‐way movement of vehicular travel from an origin (one trip end) to a destination
(the other trip end).
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Twin Falls Revisions: The City of Twin Falls Revisions to the Idaho Standards for Public
Works Construction (ISPWC), as adopted by City Council. These are also known as the
“Standard Specifications”, “Standard Revisions,” or “Construction Standards.” The most
current City Standards shall apply at the time of project approval or submittal of the
building permit.
VMT: Vehicle Miles Traveled refers to the number of miles traveled by all vehicles within a
specified area over a specified time.
Water Superintendent: That official charged with the title of Water Superintendent of the
City of Twin Falls, and/or their designee.
Work: Any Excavation, Construction, Maintenance, Repairs, or Improvements within the
Right-of- Way including any restriction of or closure of the use or access to the City’s Right-
of-Way. The term “Work” also includes any street, curb, gutter, sidewalk, sewer line, water
line or other public utility maintenance or installation.
19 | Page
1.09 GENERAL:
1. All specifications and test methods of any society, association or organization referred to
herein are hereby made a part of this Manual, including the City Standards, the same as if
fully included herein. Reference to such specifications, standards and test methods refer to
the latest edition that are in force on the date entitlement of the project is given.
2. This Manual is intended to cover only standard situations encountered in design. Non‐
standard situations that arise which are not covered in this Manual are to be designed in
accordance with accepted engineering practices, the Idaho Standards for Public Works
Construction, and the City of Twin Falls Revisions. They must contain supporting data and
be subject to approval in writing of the City Engineer and shall not be authorized in any case
for any purposes of mere convenience or economy.
3. Additional information, explanations, calculations, details, warranties, instruction manuals,
references or other design elements may be required at the discretion of the City Engineer.
4. The City does not assume maintenance responsibility for access easements, drainage
facilities, right‐ of‐way improvements, sanitary sewer, stormwater, and water facilities
(including but not limited to, their associated structures located outside the limits of
dedicated street rights‐of‐way or public easements, or which are not constructed to City
standards for public facilities).
5. Users of this manual are cautioned that other policies or standards may apply. Examples
include, but are not limited to, those provided by the Idaho Transportation Department,
Idaho Department of Environmental Quality, South Central Public Health District, Twin Falls
Fire Department, and Twin Falls City Code.
20 | Page
2.0 SUBMITTAL REQUIREMENTS AND PROCEDURES
2.01 GENERAL:
2.01.1 The procedures outlined herein apply to consulting engineers and developers seeking
approval of the civil construction plans and reports. Observing these guidelines will assist in
timely review. The overall process for planning and implementing construction projects in
the City of Twin Falls is described in this Uniform Development Design Manual and may be
found on the City’s website.
2.02 DRAWING SUBMITTAL PROCEDURES:
2.02.1 The City of Twin Falls uses an electronic submittal process for the review of civil construction
Commented \[TV10\]: Re-write this section to eliminate
pre-submittal meetings
plans. The submittal will be emailed to engineeringsubmittal@tfid.org. Submittals shall
include the civil construction plan application, associated documents, and a complete plan
set applicable to the phase.
2.02.2 Review Priority: As each civil plan set is submitted it is placed into the City’s queue of civil
construction plans to be reviewed. In a sense it is a “first come, first served” process with the
time of review added to the process. Package submittals include plans as defined in the
subsequent sections. Piecemeal submittals or those missing one or more items listed in
associated application will add time to the review. Additional engineering information
Commented \[TV11\]: Do we need to add applications into
their corresponding sections.
beyond those items described herein may be required as needed.
2.02.3 Review Time: The civil construction plan submittals shall be reviewed in accordance with a
Commented \[TV12\]: This needs to move to subdivision
section.
schedule established when plans are submitted. This schedule is based on the number of
civil plan sheets in the submittal package. Each project will receive no more than three
reviews: the first review being the longest, the second not as long and the third the shortest.
The third review is the review for approval. The City is committed to meeting the review
schedule established for a project, thereby, a development project is relatively assured of a
known time frame for plan approval. Please note the schedule assumes a time frame for the
consultant to respond to comments. It is the responsibility of the developer to confirm with
their consultant for their time required to the City’s comments. See below for the model
review schedule. If the consultant does not respond to all review comments, disagrees with
the review comments, or made significant changes to the plans by the time the third review
is submitted, it is guaranteed the plans will not be approved. If this happens there will be
subsequent review fees charged for the additional review of the plans.
2.02.42.02.3 Once plans are ready for approval the consultant will deliver three (3) hard copies signed and
sealed by a professional engineer to the City of Twin Falls for stamped approved. Two copies
will remain with the City for their use, and one will be given to the applicant for their
reproduction and distribution as needed. Once the plans are approved, they will become
property of the City and remain on file in the office of the City Engineer. These plans cannot
be modified without written permission of the Engineer of Record and the City.
2.02.52.02.4 Once a set of civil construction plans are approved, they are valid for two years from the date
they are approved. If work is not yet accepted, it is possible to extend the approval for one
year on a case by case basis and subject to current standards in place at time of extension.
21 | Page
2.02.62.02.5 Any changes to the approved civil construction plans need to be in the form of a change
order submitted to the City of Twin Falls for review and approval prior to construction.
Change orders will need to be reflected in the final As-builts.
2.03 CIVIL CONSTRUCTION PLAN REQUIREMENTS:
2.03.1 All civil construction plans and detail sheets shall conform to the following criteria and show
the following information. Additional specific requirements are discussed later in these
standards.
2.03.2 All civil construction plans and drainage reports shall be prepared by, or under the direct
supervision of, a Professional Engineer, licensed in the State of Idaho, and shall be reviewed
for the minimum requirements set forth herein and in the City Code. The submitter should
be aware that whenever unusual or serious problems are anticipated in conjunction with a
proposed development, additional information and analysis beyond the minimum
requirements of these specifications will be required.
2.03.3 The City is not responsible for the accuracy or adequacy of the design, dimensions, and
elevations on the plans (which shall be confirmed and correlated at the job site). The city,
through the approval of the development plan or drainage report, assumes no responsibility
for the completeness and/or accuracy of the development plan or drainage report.
2.03.4 Copyright Notes: Copyright notes shall not be placed on the signature sets or any reports
submitted for approval. The City must be able to make copies of the approved plans and
reports at any time without written authorization from the plan’s or report’s author.
2.03.5 This section defines the general requirements for Commercial, Residential, and/or any other
Public Improvements to be designed and constructed as public infrastructure and shall
include:
1. Public Utilities (e.g., sanitary sewer, culinary water, storm sewer, pressure irrigation, storm
water retention/detention etc.)
2. Grading and Drainage
3. Erosion control (Storm Water Pollution and Prevention)
4. Traffic signing, lighting, and traffic control (stripping plans)
5. Street improvements adjacent to and in front of all lots
a. Such improvements shall be along all dedicated streets, alleys or other easements which
connect existing improvements to the boundary of the development.
b. The layout must be compatible with the contours of the ground for proper drainage and
for servicing future development.
c. All public utilities and street improvements shall be installed to the boundary lines of the
development.
2.03.6 When development occurs beyond the reach of available utilities or undeveloped streets, it
shall be the responsibility of the developer to improve the infrastructure within the City
Right-of-Way.
1. Required improvements shall be as required by the City Engineer. Typical improvements can
include:
22 | Page
Formatted: Font: Italic
a. Streets that are conforming to the standards herein, the City of Twin Falls Master
Transportation Plan, and City revisions to the ISPWC which will accommodate all the
current and potential properties serviced by the roadway.
At no time shall the street width be less than the minimum street standard for public or
private roads (see Section 800 in ISPWC and Twin Falls Revisions TFSD-801).
Any reductions to the minimum width of minor streets shall not result in a violation of
the fire code.
Sidewalks shall be located within the city right-of-way.
2. Extend any and all required public utilities or street improvements to service the
Developer’s property.
3. Provide utilities of sufficient capacity to accommodate all the current and potential
property serviced by the utilities as required by modeling or City of Twin Falls master plans.
a. The developer is encouraged to work with adjacent property owners that may benefit
from said utility or roadway improvements for the purpose of mutual participation.
4. The developer is responsible for all upfront costs associated with the design, acquisition,
and construction of the improvements.
2.03.7 All Right-of-Way or easements necessary for development shall be acquired by the developer
and dedicated to the City of Twin Falls.
1. The acquisitions shall be at no cost to the City except as covered in other applicable City
Ordinances.
2.04 ENGINEER’S SEAL REQUIREMENTS:
2.04.1 Any plan, map, sketch, survey, drawing, document, plat, specification, estimate, and report
shall bear the seal of a Professional Engineer or Surveyor when filed with the City of Twin
Falls.
1. The signature of the individual named on the seal and the date shall appear across the face
of each original seal.
2. Each original set of final plans, specifications, reports, maps, sketches, surveys, drawings,
documents, and plats, as a minimum, shall have the original seal imprint, original signature
and date placed on the cover or title sheet.
3. The seal of the responsible party is a State requirement and applies to all documents filed
with the City of Twin Falls including but not limited to filings related to:
a. Commercial Site plans
b. Preliminary and final plats
c. Subdivision Civil Construction Plans
d. Right of Way Improvement Plans
e. Storm Water Pollution Prevention Plans
f. Specifications
g. Reports
h. Engineer’s Estimates
i. Electronic submittals with a digital stamp will be accepted per state code.
23 | Page
2.05 CONSTRUCTION DRAWINGS:
2.05.1 Complete and detailed construction plans, and drawings of all proposed improvements shall
be submitted to the City Engineering Department for review and approval prior to issuance of
a permit.
1. Construction drawings submitted for Engineering review must be drafted using a Computer
Aided Drafting program.
2.05.2 For Subdivision Civil Construction Plan design see section ? for Subdivision Construction
submittal requirements along with Streets and Right-of-Way section for design details.
2.05.3 For Site Development see section ? for Site Development Designs standards for Construction.
2.05.4 For Street and Right-of-Way design standards see section ?.
2.05.5 The plans, containing the appropriate approval signatures and the current adopted
specifications, shall be the only valid documents from which the contractor shall construct
the permitted improvements.
1. Any changes to the original plans must be approved by the City of Twin Falls in writing.
2.05.6 The contractor shall have available, at all times, at the construction site a copy of the
stamped approved plans and permit. These items shall be made available to the City’s
representative upon request.
Formatted: Highlight
2.06 REQUIREMENTS FOR AS-BUILT DELIVERABLES:
2.06.1 Prior to final acceptance of public infrastructure, As-Built drawings will be submitted in
AutoCAD format, PDF, and a paper hard copy to the City of Twin Falls Engineering
Formatted: Highlight
Department.
1. The As-Built drawings must be acceptable to the Engineering Department
Commented \[TV13\]: May need to expand on this section
to specify what particularly we will be looking for as
2. Include information on the as-built deliverables to include specifics to the phase in which it
Formatted: Highlight
acceptable.
is for (i.e., show phase lines on all plan/profile sheets, show off phase improvements
specifically, along with out of phase services. Any revised phasing through change order
process and all approved change order items.
2.06.2
24 | Page
Commented \[TV14\]: Move this to the permitting section
1.021.01 PERMITTING DELIVERABLES:
1.02.11.01.1 All work that is to be done in the public right
construction commencing, and the work shall be performed by a licensed and bonded
Commented \[TV15\]: Do contractors really have to be
bonded?
Contractor registered with the State (a public works license is not required unless under
contract with the City of Twin Falls)
1.02.21.01.1 A permit shall be required for work involving the following:
1. Right of Way
2.1. Traffic Control Sewer Main: A sanitary sewer constructed within public right‐of‐way which
transports sewage to an interceptor sanitary sewer. Sewer Mains shall start and end with a
structure.
3.1. Site Development
4.1. Floodplain
1.02.31.01.1 For more information regarding the permit process, please refer to Section 2: Permits.
3.0 PLAN AND DRAFTING STANDARDS
3.01 ACCEPTANCE OF SUBMITTALS:
3.01.1 All submittals are intended to be electronic submittals except for the last approved for
Construction documents. When hard copy plans are submitted the Administrative Assistant
has the authority to determine the acceptability of all plans submitted for signature.
Acceptability will be based on its ability to be scannedscanability, media, all required
information provided, and drafting standards outlined below.
3.02 MEDIA REQUIREMENTS:
3.02.1 When hard copy plans are submitted for approval, they shall be submitted on 20 lb., coated
bond paper. The image on paper originals submitted for approval shall not streak, smear, rub
or chip off under normal use over time. The format for plans, either hard copy or electronic
copy, shall be 24” x 36”for subdivision civil construction plans. Other submittals may utilize
Commented \[TV16\]: Think about if want to continue with
11x17
either 24”x36” or 11” x 17”. Each 24x36 Sheet shall have a minimum one and one-half inch
margin on the left edge and a one-half inch (minimum) margin on all other sides. Each 11x17
shall have a one quarter inch (minimum) margin on all 4 sides.
3.02.2 Plans that indicate the ink or toner has or is easily smeared during normal handling will be
rejected at the time of submittal. Professional seals applied to the plans shall be legible and
the ink shall be dry and non-smearing. Electronic seals are preferred. Signature on the plans
shall be done with a dark ink provided they are legible after scanning. Plans whose scanned
images have illegible Professional Seals or signatures will be rejected.
3.03 DRAFING STANDARDS:
3.03.1 The following shall apply to all plans submitted for approval.
1. Text
25 | Page
a. Minimum lettering size shall be 0.08” high (can only be used to annotate existing features
on the plans). Otherwise, minimum text height shall be 0.10”.
b. Where text is less than 0.10 inch high, text shall be all capitals.
c. All text shall be black. Professional signatures may be other dark colors provided they are
legible after scanning.
d. Recommended fonts are “Arial”, “Romans”, “Simplex”, or “Leroy”, and may include italic
or oblique text.
2. Pen weights shall not exceed the pen weights recommended for the text heights in the
chart below:
Text Height (in.) Pen Weight (in.)
0.08 0.008
0.10 0.010
0.12 0.010
0.14 0.014
0.175 0.018
0.20 0.024
3. Line Work
a. Minimum line thickness shall be 0.006 inch.
b. All line work shall be black
4. Color and Shading
5. Color may be used on electronic plans only and must contrast against the plans background.
6. Solid hatches shall be shaded between 20% and 40% and be transparent enough to not
obscure any information when scanned.
7. Hatches shall not obscure text or line work.
8. Photography used in Plans
a. Photography added to the plans shall be transparent, so the image does not substantially
degrade when printed. Such images shall not obscure any line work or text added to
them.
9. Plan Sheet Size
a. The size of the plans shall be 24 inches X 36 inches or 11 inches by 17 inches as described
above.
b. Each 24X36 Sheet shall have a minimum one and one-half inch margin on the left edge
and one-half inch (minimum) margin on all other sides.
c. Each 11X17 Sheet shall have a one-quarter inch (minimum) margin on all 4 sides.
3.04 PLAN SET INDEXING:
3.04.1 City’s policy for indexing plans is to index them by subdivision name. The subdivision name
shall be clearly shown in the Title Block on Each page of the plans
3.04.2 All sheets in the plan set shall be numbered consecutively from the cover sheet (sheet 1) to
the last sheet (usually the final drainage or SWPPP plans). (example: Sheet 1 of 10) If the
26 | Page
consultant prefers a sheet designation different than the numerical system the City requires,
those numbers may also be shown in a separate column of the index.
3.05 REVISIONS & CHANGE ORDERS:
3.05.1 Revisions are any changes to the plan set prior to final approval by the City of Twin Falls.
3.05.2 After approval by the City, any changes to the approved plans set need to be identified with
clouds and marked as a change order with sequential numbering. Only items clouded will be
reviewed and approved. Any other changes to the plan set not clouded are therefore not
approved and revert to the previous approved plan set.
3.05.3 To submit changes to the plan sheets, submit a new sheet to replace the original that is
clearly identified as a revision or change order with appropriate numbering. Such revisions
go through the same review and approval process a new submittal would go through.
3.05.4 For revisions the Engineering Department will require a full new submittal of the whole plan
set.
3.05.5 For change orders the Engineering Department will require the page be submitted through
the submittal email process clearly identifying the project name and that it is a change order
request along with 3 hard copies, signed and sealed, delivered to the engineering
department. If approved, the change order sheet will be added to the original approved plan
set.
4.0 ACCEPTANCE STANDARDS
4.01 INSPECTION OF WORK:
4.01.1 Work shall not begin until the City has reviewed and approved the construction plans and a
preconstruction meeting has taken place. Required attendees at the preconstruction
meeting are:
1. City of Twin Falls plan approver
2. City of Twin Falls lead Engineering Tech
3. City of Twin Falls Engineering Tech (Lab)
4. Engineer of Record
5. Contractor
6. Third Party Testing facility
4.01.2 The contractor shall have the stamped approved plan set onsite at all times.
4.01.3 All materials furnished by the Contractor shall be subject to the inspection and approval of
the City any time during the progress of the work and until final completion thereof. The City
shall be allowed access to all parts of the work and shall be furnished with such information
and assistance by the Contractor as is required to make a complete and detailed inspection.
4.01.4 The Contractor shall submit for a Right of Way permit for the project, identifying who the
contractor contact is, a schedule for the work, and any traffic impacts to roadways already in
use.
27 | Page
4.01.5 All construction work within the public rights‐of‐way shall be subject to inspection, and
certain types of work may have continuous inspection. It shall be the responsibility of the
contractor to provide safe access for the inspector to perform the required inspections.
4.01.6 As well as City inspections, all public improvements shall be designed and certified by a civil
engineer licensed in Idaho. The civil engineer’s professional stamp and signature shall provide
written certification to the City that all improvements, workmanship, and materials are in
accordance with current and standard engineering and construction practices; conform to
approved plans, improvement agreement, and conditions of approval.
4.01.7 Engineer’s certification is required prior to City acceptance of the public improvements, or
any portion of the improvement, for operation and maintenance.
4.01.8 The developer will incur the cost of a private third-party inspection firm.
4.02 INSPECTIONS AND CIVILITY:
4.02.1 It is the expectation of the City that all contractors and developers will be responsive to
concerns and attempt to resolve problems at the most appropriate level.
1. If problems still arise, the matter should be referred to the lead inspector, or their designee,
and if necessary, subsequently to the City Engineer.
4.02.2 The City of Twin Falls promotes mutual respect, civility, and orderly conduct among city
employees, contractors, and the public.
4.02.3 The City of Twin Falls does not intend to deprive any person of their right to ask questions.
But doing so must maintain, a safe, harassment-free workplace for city staff and responsible
parties.
4.02.4 In the interest of promoting positive development in Twin Falls, city staff encourages positive
communication and will not tolerate volatile, hostile, or aggressive behavior.
4.03 TESTING:
4.03.1 The Contractor is required to provide material testing at no cost to the City as required in
applicable construction standards and as necessary to validate the acceptability of the work.
rd
4.03.2 The material testing shall be performed by an independent 3party qualified testing firm,
identified by the contractor, and approved by the City Engineer prior to the commencement
of the work subject to testing. Test results shall be provided to the City for review in a timely
manner.
1. Qualified testing means the individual performing the test is certified by a national standard
to perform such test. Examples of national standards for testing are:
a. ISPWC
b. Public Works License
c. WAQTC
d. ASTM
e. Idaho Concrete Institute (ACI)
f. AASHTO
g. PROWAG (ADA Ramps)
28 | Page
4.03.3 Materials or work that does not meet the applicable standards will be deemed defective and
rejected by the City.
4.03.4 All testing information shall be transmitted to the City on a weekly basis.
Commented \[TV17\]: Expand on how they deliver the
information
1. The weekly information shall be sent to engineeringinspectors@tfid.org include the project
Commented \[TV18\]: Verify email address
name, phase, and utility or street information the email is being sent for.
2. For example: Subject: ABC Subdivision, phase 1, water test reports.
3. The email needs to be project specific. This may require multiple emails be sent on the
same project to break out the utilities or streets.
4.04 REMOVAL OF UNSATISFACTORY OR UNAUTHORIZED WORK:
4.04.1 Defective work or material may be rejected by the City any time before the final acceptance
of the work. Notice of such rejection shall be given, to the contractor, in writing by the City.
4.04.2 Such rejected work shall be immediately removed and disposed of to the satisfaction of the
City, and at no additional cost to the City.
Field Code Changed
4.04.3 Failure or neglect on the part of the City to reject unsatisfactory material or inferior
workmanship will in no way release the Contractor from his responsibility to provide an
acceptable product, nor shall it be construed to mean the acceptance of such work.
4.04.4 Unsatisfactory work, whether the result of poor workmanship, use of defective materials,
damage through carelessness, or any other cause found to exist prior to the final acceptance
of the work, shall be removed immediately and replaced in an acceptable manner and with
acceptable materials.
4.05 FINAL ACCEPTANCE:
4.05.1 Upon completion of the entire phase of the project as shown on the approved plan set and
when all deficiencies have been corrected to the City’s satisfaction, the City will issue a letter
of acceptance for the project phase.
4.06 WARRANTY PERIOD:
4.06.1 The Contractor shall warranty all work and materials for a period of one year from the date
that the City issues the letter of acceptance.
4.06.2 If, within said warranty period, repairs or changes are required in connection with any
guaranteed work, which in the opinion of the City is rendered necessary as the result of the
use of material, equipment or workmanship which is inferior, defective, or not in accordance
with the requirements of this Manual, the Contractor shall promptly, upon receipt of written
notice from the City, and without expense to the City:
4.06.3 Place in satisfactory condition in every particular all of such guaranteed work and correct all
defects therein.
4.06.4 Make good all damage to the site or equipment which in the opinion of the City, is a result of
the use of materials, equipment or workmanship which is inferior, defective, or not in
accordance with the requirements of this Manual; and
4.06.5 Make good any work, material, equipment, or site disturbed in fulfilling any such guarantee.
29 | Page
4.06.6 After such notice, if the Contractor fails within 30‐days to proceed to comply with the terms
of this guarantee, the City may have the defects corrected and the Contractor shall be liable
for all costs and expenses incurred; provided, however, that in case of emergency where, in
the opinion of the City, delay would cause serious loss or damage, repairs may be made
without notice being given to the Contractor and the Contractor shall pay the cost thereof.
4.07 WARRANTY WALK THROUGH:
4.07.1 60 days prior to the end of the one-year warranty period the City shall make a final
inspection. If all work has been performed and is operating satisfactorily, the City shall not
require further warranty work, thus releasing the Contractor from further obligation. All
unsatisfactory work found at the time of the final inspection shall be corrected by the
Contractor, at the Contractor’s expense.
Commented \[TV19\]: Ended here 3/11/21
30 | Page
5.0 PERMITS
Commented \[TV20\]: Move this to the permitting section
5.01 PERMITTING DELIVERABLES:
5.01.1 All work that is to be done in the public right
construction commencing, and the work shall be performed by a licensed and bonded
Commented \[TV21\]: Do contractors really have to be
bonded?
Contractor registered with the State (a public works license is not required unless under
contract with the City of Twin Falls)
5.01.2 A permit shall be required for work involving the following:
1. Right of Way
2. Traffic Control Sewer Main: A sanitary sewer constructed within public right‐of‐way which
transports sewage to an interceptor sanitary sewer. Sewer Mains shall start and end with a
structure.
3. Site Development
4. Floodplain
5.01.3 For more information regarding the permit process, please refer to Section 2: Permits.
5.015.02 RIGHT OF WAY PERMIT:
5.01.15.02.1 A permit shall be obtained prior to any work happening within the street right‐of‐way. City of
Twin Falls crews are exempted from obtaining a permit.
5.01.25.02.2 An application with plans for the proposed work must be submitted to the City for review and
approval prior to work beginning.
5.01.35.02.3 Anyone excavating within the right‐of‐way shall call Dig Line (One Call) 811 prior to any
excavation activities.
5.01.45.02.4 In the case of emergency repairs (i.e., when construction in the right of way is necessary for
health or safety reasons that could not be anticipated) a permit is still required for which
application shall be made on the same day or the next business day after the work has begun.
5.01.55.02.5 Work that partially or completely restricts any street, sidewalk or alley shall submit for review
(with Right-of-Way permit) and approval of a traffic control plan prior to any work starting.
The Contractor shall provide 24-hour advanced notice before starting work on a local street
and 72-hour advanced notice for collector and arterial streets.
5.01.65.02.6 In addition, it may be necessary to make the following notifications (including location, date,
time, and duration of the closure that was approved):
1. The City’s Public Information Officer
2. Engineering and Street Operations Departments
3. Dispatch (311) for non Emergency services
4. School District
5. Businesses and residents immediately affected
a. The Contractor is liable for incidental damage caused by construction, whether or not
those damages have been discovered at the time of construction. When the Contractor
31 | Page
performs the restoration, then the Contractor remains liable for maintaining the
restoration until such time as the street segment is reconstructed.
5.025.03 TRAFFIC CONTROL PERMIT:
5.02.15.03.1 Work that partially or completely restricts any street, sidewalk or alley requires an approved
traffic control plan prior to any work starting. Traffic control plans for street closures shall
only be approved in writing by the City Engineering Department.
5.02.25.03.2 All street closures require a Traffic Control Permit. The permit application must be received
by the City at least fifteen (15) calendar days prior to work commencing. Full Closure of
Arterial roadways is not allowed. Must provide for two-way traffic 24 hours a day.
5.02.35.03.3 The Contractor shall provide adjacent property owners twenty-four (24) hour minimum
advanced notice before starting work on local streets and seventy-two (72) hour minimum
advanced notice for collector and arterial streets.
5.02.45.03.4 All Traffic Control shall conform to MUTCD Standards and be stamped by a licensed engineer
or signed by a licensed and bonded company capable of producing compliant plans.
5.035.04 SITE DEVELOPMENT PERMIT:
5.03.15.04.1 All plans and designs shall be prepared by an engineer licensed in the state of Idaho and
submitted to the City for review and approval prior to commencement of work being
performed, and conform to the following outline of procedures:
5.03.25.04.2 The construction plans shall be submitted to the city as part of the land development
application. The city may charge a fee in an amount set by council resolution for the permit.
The plans shall be reviewed by the city for compliance with this design manual and other
applicable rules and standards prior to approval.
5.03.35.04.3 The following conditions apply to all approved construction plans:
1. Any modifications to the construction plan shall be submitted to the city for approval as a
change order.
2. Approval of the construction plan submittal does not relieve the owner or responsible party
from the duty to ensure the systems and their safety measures function as designed.
3. Approval may be suspended or revoked at any time if conditions are not as stated or shown
in the approved application or if implementation of the construction plan submittal is not
proceeding in the approved manner.
4. Approval of a construction plan submittal may be suspended if the project is not completed
within a two-year period. However, a one-year extension may be granted by the City
Engineer, upon written request, that provides the reason(s) for the delay or cessation of
development and specifies a time frame for completion or commencement of development
activities.
5. If a construction plan submittal approval is suspended or revoked, the owner shall be
required to submit a new plan for approval, with the requisite fee, prior to starting, or
continuing, the planned project or development.
32 | Page
5.03.45.04.4 Any significant changes to the approved plans prior to or during construction shall require
approval by the City Engineer prior to installation.
5.03.55.04.5 Upon acceptance of the plans by the City, the engineer shall provide the City Engineer three
sets of prints of the plans, wet stamped and signed.
5.03.65.04.6 Public improvements, including sanitary sewers, culinary water, storm sewers, streets,
sidewalks, curbs, lighting, parks, or other requirements, shall not be undertaken except after
the plans have been approved by the City and the developer has paid permit fees, and
received approval.
5.03.75.04.7 The amount of the permit fee shall be set by City Council with the annual adoption of a fee’s
resolution.
1. The City may require the developer to provide bonding or other performance guarantees to
ensure completion of required public improvements in accordance with the provisions of
the Uniform Development Code.
Commented \[TV22\]: May add note that bonding needs to
include a 20% markup for City Soft costs (Engineering,
2. All contractors and their subcontractors who work in the City rights‐of‐way must be licensed
Surveying, Construction Management, Inflated costs due to
and bonded with the State of Idaho.
being municipality)
5.045.05 FLOODPLAIN DEVELOPMENT PERMIT:
5.04.15.05.1 A Floodplain Development Permit (FDP) shall be required prior to the commencement of any
development activities within Special Flood Hazard Areas (SFHA).
5.04.25.05.2 See City of Twin Falls Uniform Development Code for requirements.
5.055.06 PERMIT APPLICATION LINKS:
5.05.15.06.1 Right of Way Permit for Trenching and Boring.
5.05.25.06.2 Traffic Control Permit
5.05.35.06.3 Site Development Permit
5.05.45.06.4 Right of Way Permit for Sidewalk, Curb & Gutter, and Driveway.
5.05.55.06.5 Flood Plain Development Permit Application.
Commented \[EAG23\]: You can accept or reject this
change and it will do the change on its own.
6.0 PLAT APPROVAL PROCESS
6.01 GENERAL INFORMATION:
6.01.1 In order to subdivide a parcel into two or more lots within the City of Twin Falls, platting is
required. Platting is also required when re-subdividing land that has been previously platted.
6.01.2 The subdivision of land is generally the first step in the development process. The platting
process essentially creates a contract between the landowner (developer) and a
governmental entity once it is approved by a governing body (i.e., City Council). Through
regulation of the subdivision of land by platting, the city acts on behalf of the public and
subsequent individual owners and/or tenants to ensure proper public improvement and land
development quality. The regulations and standards for the subdivision and improvement of
land are designed to ensure adequate light, air, open spaces, drainage, transportation, public
33 | Page
utilities, and other needs, to insure the development and maintenance of a healthy,
attractive, and efficient community that provides for the conservation and protection of the
public and an area’s natural resources.
6.01.3 Platting is the process of mapping and recording a tract of land used for development. There
are two types of plats that must be reviewed and approved before a property can be legally
subdivided: 1) the preliminary plat and 2) the final plat.
6.01.4 A preliminary plat is a map of a proposed subdivision or property showing the character and
proposed layout of the tract in sufficient detail to indicate the relationship of the proposed
development to topography, existing streets, drainage facilities, utilities, existing easements
of record, existing urban development, zoning and indicates the nature of the land planning
design.
6.01.5 A final plat is a map of a land subdivision that is filed in the office of the County Clerk, along
with the necessary affidavits, dedications, and acceptances that delineates the layout of a
subdivision or property.
6.01.6 Outlined in the following section are some common questions regarding the platting process
and the steps you will need to take in order to plat your property. Although the information
below can be helpful in understanding the City of Twin Falls’ platting process, you are
strongly encouraged to contact the Planning & Zoning and Engineering staff to discuss your
project and the platting requirements in further detail before incurring costs associated with
developing your property. Platting and plan development guidelines are outlined in greater
detail in the City of Twin Falls Uniform Development Code.
6.02 FREQUENTLY ASKED QUESTIONS REGARDING THE PLATTING PROCESS:
6.02.1 Why do I need to plat my property?
1. In order for properties to be eligible for a building permit, they must be either 1) platted, 2)
or have been included as part of the original town site (properties established before City
platting requirements). Properties not falling into one of these categories will not be eligible
for a City building permit before, during or after property sale.
6.02.2 How do I know if my property has been platted?
1. Planning & Zoning staff can check the platting of a property and can provide insight into its
conformance with a proposed use.
6.02.3 How long can a Preliminary Plat remain active?
1. Preliminary plats in the City of Twin Falls are valid for two years from the date of Planning
and Zoning recommendation of approval as described in the findings of facts, conclusion of
law. In some circumstances, you may choose to preliminary plat a piece of property but
decide to delay final platting until a later time. If any portion of the plat is final platted
within those two years, the preliminary plat will gain an additional two years of validity.
After the validity period has expired, the preliminary plat must be reapproved through the
entire process as outlined in the Uniform Development Code to be eligible for a final plat.
2. The City of Twin Falls does have an administrative process for a preliminary plat extension.
Please meet with Planning & Zoning staff for more information.
34 | Page
6.02.4 How long can a Final Plat remain active without being recorded?
1. A final plat can remain active for two years. If the plat is not recorded within two years of
the Council approval, the final plat will expire.
6.02.5 What public improvements may be required as part of the property development process?
1. Upon final platting of a property, you may be required to install or upgrade public
improvements for your property. As the construction plans are reviewed and completed,
determinations as to what public improvements will be needed for your property will be
made.
2. These may include installation of public:
a. Sidewalks
b. curb and gutter
c. streets
d. water mains
e. sewer lines
f. fire hydrants
g. storm sewers
h. alleys
i. pressurized irrigation
j. parks
k. storm drainage facilities
l. and/or other required improvements to your property.
6.02.6 How do I develop a plat for my property?
1. Applicants must utilize the services of an engineering firm and/or registered land surveyor
to develop their plat. These firms utilize professional engineering services that are required
to develop plats and public improvement plans for property owners that conform to the
plat content requirements as outlined in the City of Twin Falls Uniform Development Code
and Design Manual.
35 | Page
7.0 PREMLIMINARY PLAT
7.01 PROCESS FLOW CHART:
Preliminary Plat Process
1. Pre-Application Request Form
a. Complete Application Request Form. b. Pre-Application Meeting is Scheduled. c. Community Development Departments
review request prior to meeting.
2. Pre-Application Meeting
a. Applicant Meets with Staff with appropriate submittals as necessary.
b. Staff conveys information and requirements necessary for development to be included with the Preliminary Plat submittal. (This is a cursory review
and staff makes every attempt for it to be all encompassing, a full review will be completed with the preliminary plat submittal)
3. Preliminary Plat
b. Review of Preliminary Plat by
a. Preliminary Plat Application and c. Review Letter is sent to Applicant.
Engineering for technical items and
applicable documents are submitted. (Applicant submits revisions and
by Planning & Zoning for layout and
step 3b. is repeated as necessary)
density.
d. Preliminary Plat is scheduled with e. If Preliminary Plat is approved then
Planning & Zoning Commission for proceed to the Final Plat Process.
recommendation.
4. Preliminary Plat Process Complete
36 | Page
7.02 PRELIMINARY PLAT PROCESS:
7.03 PRE-APPLICATION:
7.03.1 Application: The subdivider shall file with the administrator a complete pre-application form.
7.03.2 Contents: Developer shall submit a basic layout of all public infrastructure on a 24” X 36”
sheet with sufficient detail to determine impacts on the existing infrastructure, etc.
7.03.3 General layout and approximate dimensions of streets, blocks and lots in sketch form:
7.03.4 Existing Conditions and characteristics of the land on and adjacent to the proposed
subdivision site
7.03.5 Areas set aside for schools, parks, and other public facilities
7.03.6 General idea of utilities needed to serve the site (to include water, sewer, storm, PI)
7.03.7 Fees: None required
7.04 PRELIMINARY PLAT CONTENTS:
7.04.1 Application: The subdivider shall submit to the administrator a complete preliminary plat
application form and all required documentation specified in the application.
7.04.2 Content of Preliminary Plat: The contents of the preliminary plat and related information
shall be in such form as stipulated by the commission; however, additional maps or data as
Commented \[TV24\]: Is this really by the commission?
deemed necessary by the administrator may also be required.
7.04.3 The subdivider shall submit to the administrator at least the following:
1. Submit in accordance with the application as approved by the City Engineer and the
Administrator. Copies of the preliminary plat of the proposed subdivision, drawn in
accordance with the requirements hereinafter stated; each copy of the preliminary plat
shall be on good quality paper.
2. A written application requesting approval of the preliminary plat.
3. Appropriate information that sufficiently details the proposed development within any
special development area, such as hillside, zoning development agreement, floodplain,
Commented \[TV25\]: Hillside still going to be in future
code?
cemetery, mobile home, hazardous and unique areas of development.
7.05 PRELIMINARY PLAT DRAWING REQUIRMENTS:
7.05.1 General
1. Legal Description- Section, Township, Range.
2. Plat drawn to scale of not less than 1” = 100’.
3. Show drafting date or revision dates if applicable.
4. Subdivision name does not duplicate the name of any other subdivision in Twin Falls County
with concurrence of Staff.
37 | Page
5. The names, addresses and telephone numbers of the subdividers, the engineer or surveyor
who prepared the plat, and any other professional persons involved in the subdivision.
6. The names and addresses of all surrounding property owners both adjacent to and beyond
any public thoroughfares from the subject property on record in the County Assessor's
office. Uniform Development code will describe the distance from boundary of property for
notifications.
7. Legal description by township, section, range
8. North Arrow
9. Vicinity Map (4 square miles).
10. A statement of the existing and intended use of the proposed subdivision, such as:
residential single-family, duplex, and multi-unit housing, commercial, industrial,
recreational, or agricultural and a showing of any sites proposed for parks, playgrounds,
schools, churches, or other public uses.
11. The land use and existing zoning of the adjacent land
12. FEMA area identified if applicable.
13. A map of the entire area scheduled for development if the proposed subdivision is a portion
of a larger holding intended for subsequent development with all phases of development
shown.
14. Contour lines, shown at five-foot (5') intervals where land slope is greater than twenty
percent (20%) and at one foot (1') intervals where land slope is twenty percent (20%) or
less, referenced to an established benchmark of the City vertical control system, including
its location and elevation.
15. A site report as required by the appropriate health district where individual wells or septic
tanks are proposed.
16. A note if this subdivision will be under a Homeowners Association and contain CC&R’s
17. Any additional required information for special developments as specified in the Uniform
Development Code and this Design Manual.
7.05.2 Water
1. Proposed water system with location and sizes labeled.
2. All services required to serve the individual lots
3. Looping required on all phases.
4. Location of Fire Hydrants identified.
7.05.3 Sanitary Sewer
1. Proposed Sanitary Sewer system with location, sizes and flow direction labeled. Must stub
to property lines for future connection and adjacent properties.
2. Include services to each individual lot.
7.05.4 Storm Drain
1. Proposed Storm Drain System with location, sizes, and flow direction labeled.
2. Storm Water Retention Facilities with storm water calculation and 100-year Flood Route
identified.
38 | Page
7.05.5 Pressure Irrigation
1. Proposed Pressurized Irrigation system with location and sizes labeled (requires air relief
and blow off apparatus).
2. Identify regional PI station that will support this development or if a new facility will be
constructed by the developer. Indicate if this station will be public or private. If private,
provide documentation on how fees, maintenance, etc. will be addressed.
3. Include services to each individual lot.
7.05.6 Streets
1. Identify existing streets, street names, R/W, curb gutter, and sidewalk.
2. Street names outside of Twin Falls Proper (E/W, N/S).
3. North/South-Street or Way.
4. East/West-Avenue or Road.
5. Cul-de-Sac’s -Circle, Court, or Place.
6. Meandering Streets- Drive, Lane, Path, or Trail.
7. Continuation of existing street names shall be used.
8. Stub Streets: Where adjoining areas are not subdivided, the arrangement of streets in new
subdivisions shall be such that said streets extend to the boundary line of the tract to make
provisions for the future extension of said streets into adjacent areas. A vehicular nonaccess
reserve strip may be required and held in public ownership. Temporary cul-de-sacs shall be
required.
7.05.7 Layout
1. Design to comply with Roadway design standards located in subsequent sections.
2. Phasing Identified. Final Plats to be sequentially numbered and labeled Number 1, Number
2, Number 3, etc. Construction phases to be sequentially labeled Phase 1, Phase 2, Phase 3,
etc.
3. Dead-ends shall be identified. If less than 150 feet barricades will be required at the phase
lines. If longer than 150 feet a fire department turn around will be provided.
4. Location and length of lot lines/ boundaries.
5. Proposed Lot and block numbers.
6. Lot and subdivision areas shown.
7. Existing contour lines shown 200-feet outside boundaries.
8. Benchmark shown.
9. Approximate lot corner and easement’s locations of all adjacent subdivisions.
10. Locations of existing and proposed streetlights.
11. Note that no backing is allowed onto collectors. Accesses onto Arterials and Collectors will
be determined by the City Engineer and spacing shall comply with the Transportation
Master Plan.
7.05.8 Existing Utilities must be shown.
1. Domestic water main location and size.
2. Sanitary Sewer Main location, size, and flow direction.
39 | Page
3. Storm Drain Main location, size, and flow direction.
4. Pressure Irrigation location and size.
5. Gravity Irrigation Laterals location, size, and flow direction.
6. Location of gas lines, power lines, telephone, or other.
7. If no utilities exist, location and direction to nearest sources.
8. Statement for Improvements to existing utilities and also any on site improvements to be
made.
7.05.9 Easements
1. Dedications/Easements public and private, location, dimension, and purpose.
a. Easements will be a minimum of 7.5 feet from centerline of any utility to the edge of
easement.
2. Pedestrian/Bike Path from Cul-de-Sacs to Collector and Arterial Streets.
7.05.10 Fire Requirements
1. Minimum of 2 fire access routes required for more than 30 non-sprinkler residential units.
2. Minimum 20-foot-wide access. Buildings taller than 30 feet require 26-foot-wide access.
3. Accesses exceeding 150 feet require Fire Department turn around.
4. All lots located within 300-feet of a hydrant (Arterials and Major Collectors shall have
hydrants on both sides so as to not require full road closure for fire hoses).
5. Tees for hydrants require valves.
6. All fire lines require valves at main line and are limited to 150-foot max length to building.
7.05.11 Fees
1. A fee for processing and checking a preliminary plat shall be due at the time upon submittal
of the preliminary plat to the Administrator. The amount of the fee shall be as adopted by
the City Council and is listed on the latest submittal application.
7.05.12 The Preliminary Plat approval will not dictate construction plan standards. Construction
plans will be approved at current adopted standards in place at time of review.
7.06 PRELIMINARY PLAT SUPPORTING DOCUMENTS:
7.06.1 Names and addresses of surrounding property owners. Radius determined by the Planning &
Zoning Department.
7.06.2 To ensure adequate water supply to each new subdivision/development, all
subdivision/development preliminary plat applications to the city will include water modeling
results, from the City’s appointed modeling company, which indicates the new
subdivision/development can be developed in a manner that will provide adequate water
supply for domestic water and fire protection and the new subdivision/development will not
adversely affect the city's ability to continue to provide adequate domestic water and fire
protection to the existing water system users. The preliminary plat will indicate what flow
rate the development was modeled at. Future Will Serves will reflect this requested flow
rate.
7.06.3 To ensure adequate sewer conveyance and treatment service by the city, each
subdivision/development preliminary plat application to the city will include sewer service
40 | Page
conveyance and treatment modeling results, from the City’s appointed modeling company,
which indicates the new subdivision/development can be developed in a manner that will
provide adequate sewer service and sewer treatment capacity by the city and the new
subdivision/development will not adversely affect the city's ability to continue to provide
adequate sewer treatment capacity to the existing sewer system users. The preliminary plat
will indicate what flow rate the development was modeled at. Future Will Serves will reflect
this requested flow rate.
7.06.4 The cost of the water and sewer modeling will be the responsibility of the developer.
7.06.5 South Central Health District site report of wells and septic if applicable.
7.06.6 Copy of CC&R’s and Deed Restrictions.
Commented \[TV26\]: Ended page 42 at final platting
3/24/2020
41 | Page
Commented \[TV27\]: Add Flow Chart for Final Plat
8.0 FINAL PLATTING
process
Also add final plat process
8.01 FINAL PLAT FLOW CHART:
8.02 FINAL PLAT APPLICATION:
8.02.1 The subdivider shall file with the administrator a complete final plat application form and all
required documentation specified in the application.
8.03 FINAL PLAT CONTENTS:
8.03.1 The contents of the final plat shall include and be in compliance with all items required under
title 50, chapter 13 of the Idaho code and generally conform to the approved preliminary plat
with Planning and Zoning conditions of approval and follow acceptable engineering practices
and local standards established by the administrator.
8.03.2 Fees:
1. A fee for processing and checking a final plat shall be due at the time upon submittal of the
final plat to the Administrator. The amount of the fee shall be as adopted by the City
Council and is listed on the latest submittal application.
8.04 FINAL PLAT DRAWING REQUIREMENTS:
8.04.1 Subdivision name shall match the Preliminary Plat. Sequential plats to be numbered Number
1, Number 2, Number 3, Etc. (Abbreviation of “NO 1” will not be accepted)
8.04.2 Written description matches platted description. Description to be continuous.
8.04.3 Year of Recordation
8.04.4 North Arrow
8.04.5 Scale
8.04.6 Engineering firm’s name on plat.
8.04.7 Sheet numbers noted. (ex. 1 of 3)
8.04.8 Legend noting boundaries, lot lines, easement lines (and uses), pins set, found, etc.
8.04.9 Vicinity Map- (four square miles with North Arrow).
8.04.10 Ties to two government corners
8.04.11 Basis of bearing noted
8.04.12 Section corner number noted
8.04.13 All found pins noted and numbers noted.
8.04.14 Boundary pins shown for all boundary points.
8.04.15 All section lines (street center lines labeled).
8.04.16 Surrounding subdivisions and unplatted areas noted.
8.04.17 Right-of-Way dedication per Roadway section of this manual.
8.04.18 Note that all lots shall have access from local streets only (no access from collectors or
arterials where lots have more than one street frontage).
42 | Page
8.04.19 Street names no duplicates. See Pre-plat section for Ave., St, Dr, Circle, Lane, etc. Private
access easements shall be named when serving 6 or more units
8.04.20 Lots, Tracts, and Block numbers
8.04.21 Lot area in Square Feet
8.04.22 Curve and line data if applicable
8.04.23 Boundary Bearings and distances (match Metes and Bounds description on Signature sheet)
8.04.24 Interior lot line bearings and distances (sum match exterior boundary lengths)
8.04.25 Right-of-Way dedications if applicable
8.04.26 Easements width and description labeled (can be in a legend)
8.04.27 Other requirements as required by state licensing board or state code.
8.05 SIGNATURE SHEETS:
8.05.1 Certification of ownership
8.05.2 Dedications of Rights-of-Way, Parks, Easements, and must specify who has the right to use
them where applicable. Notes section to include that Right-of-Way and easements will be
dedicated to the City of Twin Falls upon recordation of the final plat. A separate note that
parks will be dedicated by separate deed to the City upon acceptance of the required
improvements for parks.
8.05.3 Water System note
Commented \[TV28\]: add the actual language under this
bullet
8.05.4 Irrigation Water note
8.05.5 Health Certificate on front page for South Central Health District
8.05.6 Notary for owner’s signature
8.05.7 Surveyor’s Certification
8.05.8 City Council (Mayor and Deputy City Clerk)
8.05.9 City Engineer (City Engineer and Attest)
8.05.10 County Surveyor
8.05.11 Acknowledgment for the county Surveyor
8.05.12 Twin Falls Highway District (if applicable)
8.05.13 County Treasurer
8.05.14 County Recorders
8.06 FINAL PLAT SUPPORTING DOCUMENTS:
8.06.1 Title Report or Subdivision Guarantee
8.06.2 Proof of current ownership of the real property included in the proposed final plat.
8.06.3 Statement of Authorization (who has authority to sign for a partnership or LLC, etc.)
8.06.4 Affidavit of Legal Interest (Authority if someone is representing the owner’s interest) see
standard forms section
8.06.5 One (1) copy of Preliminary Plat of sufficient size and clarity that conforms to the approved
preliminary plat showing any additional requirements stipulated by the P&Z commission.
43 | Page
8.06.6 One (1) copy of the Final plat, drawn in accordance with this section, 18”x27” in size and in
compliance with the approved Preliminary Plat and additional requirements.
8.06.7 Copy of the recorded PUD/ZDA (if applicable)
8.06.8 Twin Falls Highway District or other necessary jurisdiction Approval (if applicable)
8.06.9 Twin Falls Canal Company Approval letter. A copy of the recorded agreement (if applicable)
8.06.10 Trust Agreement (if applicable)
8.06.11 Engineers Estimate for public infrastructure approved by the City Engineer
8.06.12 Financial guarantee of improvements (if applicable) = 120% of engineers estimated value of
public infrastructure approved by the City Engineer
8.06.13 An Improvement Agreement for Developer’s for each phase signed by the developer
8.06.14 Closures for each Lot, tract, boundary, etc.
8.06.15 Copy of Recorded Offsite Easements
8.06.16 Weed management plan signed by the developer
8.07 PRIOR TO SIGNATURES:
8.07.1 Water and Sewer Modeling Reimbursed
Commented \[TV29\]: this may change
8.07.2 TFCC Certificate of Water Shares transferred to the City of Twin Falls (1 share per acre).
8.07.3 Payment of all applicable Fees
8.07.4 Parks in Lieu fee paid
8.07.5 Bonds delivered to the City of Twin Falls or Trust Agreement to accompany the Plat for
recordation.
8.07.6 Construction plans will need to be approved for streets, water, sewer, stormwater, parks,
gravity irrigation and pressure irrigation systems prior to Signatures.
8.07.7 Deeds for Tracts to appropriate entities shall immediately follow recordation. (think about
how parks are dedicated if they are not developed yet and which note needs to be on the
final plat transferring property)
44 | Page
9.0 HYPERLINKS TO SUPPORTING DOCUMENTS AND
APPLICATIONS
9.01.1 All of the following are hyperlinked to their corresponding documents:
1. Affidavit of Legal Interest
2. Easement document
3. Final Plat Application
4. Financial Guarantee (bonds, letters of credit, check, trust agreement)
Commented \[TV30\]: add standard form for bond and
check
5. Improvement Agreement for Developers
6. Mylar Submittal Form
7. Parks In Lieu Application
8. Pre-Application Request Form
9. Preliminary Plat Application
10. Preliminary-Final Plat Application
11. Right of Way dedication document
12. Subdivision Application Fees
13. Trust Agreement
14. Water Share Transfer Form (TFCC water shares)
15. Weed Management Plan
10.0 SUBDIVISION CONSTRUCTION DRAFTING STANDARDS
10.01 GENERAL CIVIL CONSTRUCTION PLAN REQUIREMENTS:
10.01.1 The following instructions are for the purpose of standardizing the preparation of drawings to
obtain uniformity in appearance, clarity, size, and style. These plans and designs shall meet
the Civil Construction plan standards as defined here, along with the following information.
10.01.2 The minimum information required on drawings for improvements are as follows:
10.01.3 All drawings shall be clear and legible and conform to good engineering and drafting practice.
The drawings must be completed using a Computer Aided Drafting program.
10.01.4 Size of drawings sheet shall be 24 inch X 36 inch with a 1 inch minimum border on left side
and ½ inch minimum on the remaining three (3) sides or 11” X 17” with a ¾ inch minimum
border on the left side and a ¼ inch minimum border on the remaining three (3) sides.
10.01.5 An electronic copy in pdf form of the drawings shall be submitted for review. A hard copy
may also accompany the electronic submission. All submissions must be appropriately
stamped & signed following IPELS requirements.
10.01.6 In general, the following shall be included on all drawings unless otherwise directed by the
Engineering Department:
1. North arrow (plan view)
2. Scale:
45 | Page
a. 1" = 50’ horizontal (maximum in plan and profile 1”-100’ master plans)
b. 1" = 5' vertical (maximum)
c. Scale of each Detail
d. Other appropriate scales as approved by the City Engineer
3. Elevations referenced to NAVD 88. (North America Vertical Datum 1988)
a. No assumed elevations will be acceptable without an equation to tie the assumed
elevations back to actual elevations.
4. Stationing and elevations for profiles.
10.02 DRAWING REQUIREMENTS:
10.02.1 Cover Sheet needs to include, but not limited to, the following information:
1. Required Notes: These notes shall appear on the cover sheet as a minimum. If a cover
sheet has not been used, they shall be put on every sheet of the submittal.
2. City of Twin Falls plan review is only for general conformance with the City of Twin Falls
design criteria and the City Code. The City is not responsible for the accuracy and adequacy
of the design, dimensions, and elevations which shall be confirmed and correlated at the
job site. The City of Twin Falls, through the approval of this document, assumes no
responsibility for the completeness and/or accuracy of this document.
3. All roadway construction shall conform to the City of Twin Falls Roadway Design and
Construction Specifications, latest adopted edition.
4. All water distribution, sanitary sewer, and storm sewer construction shall conform to the
City of Twin Falls Standards and Specifications, latest adopted edition.
5. All materials and workmanship shall be subject to inspection by the City. The City reserves
the right to accept or reject any materials and workmanship that does not conform to the
City standards and specifications.
6. The Contractor shall notify the City and hold a preconstruction meeting prior to any work
commencing.
7. The Contractor shall have one signed copy of the plans (approved by the City of Twin Falls),
one copy of the appropriate standards and specifications, and a copy of any permits,
improvement agreement needed at the job site at all times.
8. It is the Consultant’s responsibility to accurately show existing conditions, both on-site, and
off-site, on the construction plans. Any modifications needed due to conflicts, omissions, or
changed conditions either on-site or off-site, which arise in the field, will be entirely the
Developer’s responsibility. The cost to rectify any adverse situation to meet the City
Standards and Specifications and the City Code shall not be borne by the City of Twin Falls.
9. All signage and striping shall be in accordance with the Manual of Uniform Traffic Control
Devices, unless otherwise noted by the City of Twin Falls.
10. Vicinity map showing 4 square miles around the project
11. Index map for complex plans
12. General, Water, Sanitary Sewer, Pressure Irrigation, Stormwater, and Construction notes
46 | Page
13. Legend, Sheet Index, Abbreviations, Design Data (Name, address, phone, etc. of engineer or
firm preparing drawings with license number, stamp, and signature, Owner/Developer
contact information, Development Area, Existing and Proposed Zones, Existing and
Proposed Uses, Setbacks, Public Utility Notes, Private Utility Notes, Joint Trench Utility
Notes, Easements.) Project name, description, location, and year of submittal
14. Title blocks, located along the right side of the sheet to include:
a. Project Title (subdivision, site plan, etc.)
b. Engineering Firm Logo with name
c. Revisions description0
d. Engineer of record stamp
e. Sheet number
15. As-Built drawings shall be provided prior to acceptance of improvements and be in
conformance with the As-Built submittal requirements.
Commented \[TV31\]: Create an as-built section with
standards of submittals
10.02.2 The plan view shall include, but not limited to, the following information:
1. Show property and/or R.O.W. lines, easements and/or tracts. Type and dimension of
easement or tract shall be clearly labeled. R.O.W. and street widths shall be dimensioned.
Label lot and blocks.
2. Survey lines and stations shall be based on centerline stationing only. Use continuous
stationing for each street progressing from left to right and shall be coordinated with the
profile. Stationing shall be equated to and from flow line stationing at bulbs, horizontal
radius curbs, and other departures from normal roadway cross sections, (i.e., the pavement
cross slope is not 2%, and at least 200’ from all intersections). Stationing shall be equated
to flow line stationing at cul-de-sacs. Also, if the roadway is horizontally curved, whenever
the grade is less than 0.70%, separate flow line profiles are required as the basis for design.
3. Show sidewalks, roadways, and roadway names.
4. Show existing and proposed utilities and structures, including, but not limited to; water
valves, fire hydrants, sanitary sewer manholes, storm drainage facilities (i.e., inlets,
manholes, etc.), telephone, gas, electric, ditches or swales, curbs and gutters, pavement
limits, bridges or culverts, guardrails, etc.
5. Where curb returns are installed at private access streets or drives, sidewalk easements
shall be dedicated to back of Standard Curb ramp ADA access. In situations where this type
of access is anticipated to warrant a traffic signal in the future an additional traffic signal
easement shall be included for the placement of the traffic signal poles and associated
equipment. Coordinate with the Traffic Technician for this easement. If the plat has
already been recorded, these easements shall be done by separate document before the
civil plans are approved.
6. Label Station and critical elevation (flow line, invert of pipe, etc.) of all utility or drainage
appurtenances, existing and proposed.
7. Flow direction arrows, particularly at intersections.
8. Match lines and associated sheet numbers.
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9. Station and elevation of all curb return; horizontal PC’s PT’s, PITC’s etc. high or low point of
all vertical curbs, existing and proposed.
10. Curb return radii, existing and proposed
11. Complete horizontal curve data: (R, Delta, L, PC Sta.)
12. Centerline stations of all residential driveway curb cuts.
13. Show typical roadway cross section for all roadways, existing and/or proposed. These cross
sections shall appear on a details sheet or cover page. They shall indicate the type of
roadway(s); profile grade design point (centerline, flow line, top of curb, lip of gutter, etc.);
roadway width, R.O.W.; type of curb, gutter, and sidewalk; pavement cross slope, that the
material section will be in conformance with the current adopted ISPWC and City revisions,
etc.
14. Basis of plan view and profile elevations shall be the same, i.e., flow line and flow line, top
of curb and top of curb, etc.
15. Show all permanent asphalt patching per COTF standards and specs.
16. Where the widening of an existing street occurs, provide existing spot elevations along the
edge of proposed cut line at a maximum of 50’ stations. Provide profile sections showing
cross slopes in these cases.
17. For concrete paving on City Streets a jointing plan must be submitted. Where an existing
intersection is partially constructed with concrete pavement and when the adjacent
property next to the unconstructed portion of the intersection develops, the remaining
portion of the intersection shall be completed with concrete.
18. Show irrigation control sleeving locations for medians and CAM strips where required.
19. Show any proposed construction phasing. It must be coordinated with any main extension
agreements associated with the utilities as well as any planning documents.
20. For any intersection with non-standard geometry, a detail of the intersection with the
appropriate design vehicle tracking templates shall be shown along with proposed stripping
plans.
21. Show existing infrastructure information for a distance of 100' minimum extending outside
of project boundary when connecting to existing improvements.
22. FEMA Floodplain and Floodway information.
23. Enough topographic detail to determine where the historic drainage came onto and left the
site
10.02.3 The profile shall include, but not be limited to, the following information:
1. Show original ground (dashed) and each design grade (heavy, solid). Both grades shall be
plainly labeled.
2. For 6” vertical curb and gutter, or mountable curb and gutter, all design elevations shall be
top of curb, lip of gutter, or flow line (preferred).
3. Stationing shall be set up to go from left to right and be continuous for the entire portion of
the roadway shown in plan view
4. Existing utilities
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5. Station and elevation of all vertical grade breaks, existing (as built) and proposed. The use
of grade breaks within proposed construction is discouraged and should be minimized. The
higher speed roadway shall have even less grade breaks. A numerical difference of 1.00% or
greater requires a vertical curve. Minimum of 100’ or AASHTO requirement, whichever is
larger. A 50’ VC will only be allowed in situations where drainage at an intersection is being
addressed and the intersection is a stopped condition. Where street widening occurs with
curb and gutter, multiple grade breaks to match the existing profile is not acceptable.
Utilize asphalt overlays to best fit a curb line profile and to provide a smooth transition back
to the existing pavement.
6. Distance and slope (percentage) between grade breaks and VPI’s.
7. Show vertical curves, when necessary, with VPI VPC, and VPT, high or low point (if
applicable) stations and elevations. All vertical curves shall be labeled with length of curve
in feet (L) and K (=L/A) where A = algebraic difference in grades in percent.
8. Separate flow line (or top of curb) profiles are required as the basis for design at “bulbs”
cul-de-sacs, horizontal curves and when the vertical grade is less than 0.70%, any departure
from normal roadway cross sections, i.e., the pavement cross slope is not 2%, and for at
least 200’ from all intersections.
9. Show construction phasing. This phasing of construction must be coordinated with utility
extensions.
10. Water line, sanitary sewer, storm sewer, and gravity irrigation profile information as
described below. If profile view becomes too cluttered separate sheets may be provided to
clarify the utility information.
11. Plan must include existing elevations obtained from field survey/pothole when potential
conflicts, cover, or clearance requirements exist.
10.02.4 Round-a-bout plans shall include, but not limited to, the following information:
1. Layout details at a 1"=20’ for the roundabout including the splitter islands, cross walks, and
bicycle ramps, if provided. Flow line profiles shall be provided
2. Along the curb and gutter flow line of the truck apron curb.
3. Along the curb and gutter flow line for the splitter islands and along the inscribed circle, or
roundabout circumference.
4. Along the curb and gutter flow lines for both sides of the right turn by-pass lanes
5. Profiles of alignments identified above shall be used for construction layout.
6. Layout details for any cross walks and bicycle ramps if utilized
7. Elevation at low points, high points, island noses, and 25 foot intervals within the circulator
roadway.
8. Half sections at 25 foot intervals along the splitter islands when the roadway begins to
separate. The half sections may be “restitched” for the final cross section sheets, if
provided.
9. For design of the Round-a-bout see the roadway section of this manual.
10.02.5 Sanitary Sewer drawings shall show:
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1. In addition to the requirements set forth in the General Civil construction plan
requirements, the following information shall be shown on all Sanitary Sewer plans
submitted for review and approval.
2. Location, size, invert and slope of all pipes. See Minimum pipe size requirements located in
Sanitary Sewer Design Standards.
3. Type of mainline pipe material.
4. Plan view to show stationing and offset of manhole center lines (use road centerline
stationing if available),
5. Indicate stationing and offset of service stub out as it crosses the property line.
6. Plan and Profile, bearings, and lengths of segments when not parallel with centerline of
road or easement.
7. Profile view include Manhole size, station/offset, Invert elevations, and rim elevations.
8. Profile crossings of all other existing or proposed utilities with invert elevation with type and
size of utility.
9. All existing utilities within and adjacent to area proposed for construction. Must include
actual existing elevations obtained from field survey/pothole where potential conflicts,
cover, or clearance requirements exists.
10. Details at 1" = 10' or other appropriate scale to adequately provide required information.
An overall development plan view of the sewer on master utility sheet (Maximum
Horizontal scale 1" = 100').
10.02.6 Culinary Water drawings shall show:
1. In addition to the requirements set forth in the General Civil construction plan
requirements, the following information shall be shown on all water distribution plans
submitted for review and approval:
a. Location and size of water mains, valves, hydrants, appurtenances, etc. See Minimum
pipe size requirements located in Water Design Standards.
b. Type of pipe material, hydrants, valves, appurtenances.
c. Plan view to include stationing of valves, hydrants, crossings, and any other appurtenances
or necessary for design.
d. Stationing and offset of services with elevation
e. Profile of new proposed water main shown on plan and profile sheets
f. Bearings and lengths of segments when not parallel with centerline of road or easement.
g. Profile crossings of all other existing or proposed utilities with invert elevation with type
and size of utility.
h. Details at 1" = 10' or other appropriate scale to adequately provide required information.
i. When development occurs across pressure zones include PRV stations into improvement
designs. PRV’s are to be located outside traffic ways.
j. All existing utilities within and adjacent to area proposed for construction.
k. Must include actual existing elevations obtained from field survey/pothole where
potential conflicts, cover, or clearance requirements exists.
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l. An overall development plan view of the water shown on master utility sheet (Maximum
Horizontal scale 1" = 100').
m. Dead end water mains shall be avoided whenever possible and should not exceed one
hundred fifty (150) feet in length measured from the main to the appurtenance or end.
n. Hydrants shall be located at the street intersection or at the lot line between adjacent
properties. The hydrant shall be installed per the typical detail. Hydrants shall have a
minimum of three (3) feet clear space around the full circumference of the hydrant.
Hydrant spacing shall be a maximum of 300 feet in commercial districts and a maximum of
500 feet in residential districts measured along the street centerline, unless otherwise
dictated by the Fire Chief.
10.02.7 Storm Sewer drawings shall show:
1. In addition to the requirements set forth in the General Civil construction plan
requirements, the following information shall be shown on all Storm Sewer plans submitted
for review and approval:
a. Location, size and slope of mains and lateral connections. See Minimum pipe size
requirements in Storm Sewer Design Standards.
b. Location, size and details of inlets, junction boxes, etc.
c. Plan view to include stationing and offsets of manhole center lines, inlet structures,
control structures, and crossings.
d. Manhole size, station/offset, invert elevations, and rim elevations.
e. Flow rate (50-year storm for main lines), HGL and velocity (all indicated in profile for each
pipe section).
f. Type of mainline pipe material.
g. Profile crossings of all other existing or proposed utilities with invert elevation with type
and size of utility.
h. All existing utilities within and adjacent to area proposed for construction.
i. Must include actual existing elevations obtained from field survey/pothole where
potential conflicts cover or clearance requirements exists.
j. Details at 1" = 10' or other appropriate scale to adequately provide required information.
k. On one sheet show proposed storm drain system, including sub-drain tributary areas,
inlets and other structures. Provide Curb calculations to verify the storm water does not
exceed top back of curb along with supporting calculations for storm drainpipe lines.
l. An overall development plan view of the storm sewer shown on master utility sheet
(Maximum Horizontal scale 1" = 100').
10.02.8 Retention Facility Plans:
1. In addition to the requirements set forth in the General Civil construction plan
requirements, the following information shall be shown on all retention facility plans for
review and approval:
a. Plans showing site general layout and location of retention facility on the Tract or Lot.
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b. Existing and proposed contours at one-foot intervals for retention facility. Must show how
the proposed contours will tie into the existing contours.
c. Details at 1" = 10' or other appropriate scale to adequately provide required information
d. All existing utilities within and adjacent to area proposed for grading.
e. Must include actual existing elevations obtained from field survey/pothole where
potential conflicts cover or clearance requirements exists.
f. Detention facility details as well as inlets, outlets, and piping facilities.
g. Calculations to substantiate design. (See storm drain section for more information)
h. General, Grading and Construction notes. Drainage arrows showing general direction and
slope of drainage routes along with 100 year overflow and historical drainage routes.
i. All retention ponds side slopes shall be no greater than 4(H):1(V) (6H:1V) when City
facilities) (6 and the bottoms sloped to a low spot for nuisance water. Detail of how to
keep the bottom of the retention facility free of nuisance water. All facilities shall be able
to drain completely in 96hours. Show details of how this will be accomplished.
j. Roadway drainage shall be located within appropriate dedicated drainage only easements
or right-of-way and no other utilities can be co-located with said retention facility. All
Public maintained facilities shall be above ground or an approved alternate with 95% min
void space and appropriate inspection/cleaning manholes.
10.02.9 For public maintained facilities see Parks and Rec standards for requirements.
1. HOA’s that wish to maintain the retention areas are to have language in the CC&Rs to
discuss maintenance and how to assess fees.
10.02.10 Storm Water Pollution Prevention Plan (Erosion Control Plans).
1. In addition to the requirements set forth in the General Civil construction plan
requirements, the following information shall be shown on all Storm Water Pollution
Prevention Plans submitted for review.
a. Plans showing site general layout and drainage patterns and outlets for water exiting
construction site.
b. Details at 1" = 10' or other appropriate scale to adequately provide required information.
These may include, but are not limited to, check dams, berms, de-silting fences, sandbag
and/or hay bale details and other BMPs as may be applicable.
c. De-silting basin details as well as inlets, outlets, and piping facilities.
d. Calculations to substantiate design (include in submittal but not required to be shown on
plans).
e. Erosion Control Construction notes.
f. Plan shall include an emergency phone number and name of the Developer’s responsible
person who will be available 24 hours a day should an emergency situation arise.
g. Construction Entrance/Exit Stabilization details.
h. Storm Drain Inlet Protection.
i. Dust Control measures.
j. Show all BMP’s being used on the general layout.
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k. Indicate construction and BMP sequencing for project on plan.
10.02.11 Traffic Signing and Traffic Control Plans.
1. In addition to the requirements set forth in the General Civil construction plan
requirements, a Street Lighting Plan is required and the following information shall be
shown on all Street Lighting plans submitted for review and approval for all public streets.
a. All traffic signing and traffic control plans shall be designed and installed according to
current (MUTCD) the Manual on Uniform Traffic Control Devices.
b. All traffic signing and traffic control plans shall be submitted to the City of Twin Falls
Traffic Technician for review and approval prior to field installation.
c. All plans shall include information for a 24 hour emergency contact.
d. All Traffic control plans shall be accompanied by a schedule detailing the workflow and
time frame.
e. Traffic Signals and luminaire Plans:
f. Show property and/or R.O.W. lines, easements and/or tracts, and lot lines. All streets
shall be labeled.
g. Identify curb, gutter, and sidewalk, private driveways, fire hydrants, and inlet locations.
h. Show any existing streetlights and label as existing.
i. Show any proposed trees or landscaping installations in the R.O.W. that may have future
impacts to street light placement.
j. The street light plan shall include the minimum amount of information required in
subsequent sections and a scale of 1” = 100’ is recommended to minimize the number of
plan sheets submitted. An overall development site plan that meets the scaling
requirements and fits on one plan sheet is acceptable for the Street Lighting Plan
submittal. The street lighting information may be placed on the signing and striping plan.
k. All infrastructure shall be designed in accordance with the requirements established by
the City of Twin Falls Engineering Standards
l. Construction plans shall be accompanied by a schedule of how work will be completed in
the right of way
m. As-Builts will be delivered to the City once completed.
10.02.12 Review Time: The civil construction plan submittals shall be reviewed in accordance with a
Commented \[TV32\]: This needs to move to subdivision
section.
schedule established when plans are submitted. This schedule is based on the number of
Commented \[EAG33R32\]: Is this the right location?
civil plan sheets in the submittal package. Each project will receive no more than three
reviews: the first review being the longest, the second not as long and the third the shortest.
The third review is the review for approval. The City is committed to meeting the review
schedule established for a project, thereby, a development project is relatively assured of a
known time frame for plan approval. Please note the schedule assumes a time frame for the
consultant to respond to comments. It is the responsibility of the developer to confirm with
their consultant for their time required to the City’s comments. See below for the model
review schedule. If the consultant does not respond to all review comments, disagrees with
the review comments, or made significant changes to the plans by the time the third review
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is submitted, it is guaranteed the plans will not be approved. If this happens there will be
subsequent review fees charged for the additional review of the plans.
10.02.13 Subdivision Construction Plan Review Timelines
Civil Construction Plans Up to 25 sheets 25-59 sheets 60-79 sheets**
st
1 City Review 15 days 20 days 25 days
Consultant Revisions on 5 days 5 days 5 days
st
1 Round
nd
2 City Review 10 days 15 days 20 days
Consultant Revisions on 5 days 5 days 5 days
nd
2 Round
Final City Review and 5 days 10 days 10 days
Approval
Total Working Days 40 days 55 days 65 days
Plan sets of 80+ sheets, please contact Engineering Department for schedule.
54 | Page
11.0 SUBDIVISION DESIGN STANDARDS
11.01 GENERAL:
11.01.1 Project improvements must be installed in accordance with the approved plans, the Idaho
Standards for Public Works Construction (ISPWC), the City of Twin Falls revisions to the
ISPWC standards, and any other Federal and State or local jurisdiction requirements.
11.01.2 The contractor shall have a City and DEQ approved construction plan set on site at all times
for the phase they are constructing.
11.01.3 The City will assign an Inspector to monitor construction.
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11.01.4 The Developer is required to provide and pay for 3 party material testing during
construction.
11.01.5 Acceptance of the work is based on material test results meeting or exceeding minimum
standards as defined by the ISPWC version approved with the plan set, APWA, AWWA, City of
Twin Falls revisions, State of Idaho, or another approved agency.
11.01.6 The Contractor is responsible to contact the City of Twin Falls to setup inspections
11.01.7 Upon completion of the project improvements, a final inspection will be required.
11.01.8 Any punch list items must be complete within 30 days from issuance. Contractor shall
contact the City once completed for verification.
11.01.9 If all work and punch list items are completed then a final acceptance date is assigned.
11.01.10 The Final acceptance date begins the one-year warranty period.
11.01.11 The City will require a bond for a value of 5% of the Engineers original construction estimate
for the full value of the phase during the one-year warranty period.
11.01.12 Record Documents or “As-Built” plans must be submitted to the City prior to obtaining
acceptance of the work.
11.02 PRE-CONSTRUCTION MEETING:
11.02.1 The Pre-Construction meeting is to be held prior to beginning each phase of construction to
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review the project requirements with the Developer, Developer’s Engineer, 3 party site
inspectors, Contractor, the City designated Engineer, and City inspection Department.
11.02.2 The Standards and Specifications, schedule, and the testing requirements applicable to the
project will be reviewed at this meeting.
11.02.3 Construction Project improvements must be installed in accordance with the approved plans,
the Idaho Standards for Public Works Construction (ISPWC), the City of Twin Falls revisions to
the ISPWC standards, and any other Federal and State or local jurisdiction requirements.
11.03 MINIMUM DESIGN STANDARDS REQUIRED:
11.03.1 All plats submitted pursuant to the provisions of this section, and all subdivisions,
improvements and facilities done, constructed, or made in accordance with said provisions
shall comply with the minimum design standards set forth hereinafter in this chapter;
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provided, however, that any higher standards adopted by any highway district, state highway
department or health agency shall prevail over those set forth herein.
Commented \[TV34\]: Move up to Subdivison section
11.04 REQUIRED IMPROVEMENTS:
11.04.1 Every subdivider shall be required to install the following improvements in accordance with
the conditions and specifications as follows:
1. Monuments: Monuments shall be required as per Idaho Code.
2. Streets and Alleys: All streets and alleys shall be constructed in accordance with this design
guide and the standards and specifications adopted by the City Engineer.
3. Curbs and Gutters: Curbs and gutters shall be constructed on all streets.
4. Bicycle Pathways: A bicycle pathway shall be provided within all subdivisions, as part of the
public right of way or separate easement, as may be specified in an overall bicycle plan as
adopted by the council and the MTP.
5. Installation of Public Utilities: Underground utilities shall be required in all new subdivisions.
6. Existing utilities or new large transmission lines shall not be required to be buried. If a
utility needs to be relocated for development, it will be considered new and will be buried
at that time.
7. Driveways: All driveway openings in curbs shall be as specified by the City Engineer, Twin
Falls Highway District or Idaho Transportation Department.
8. Storm Drainage: Refer to the storm water section of this design manual for drainage
requirements.
9. Public Water Supply, and Sewer Systems: All new public water supply or sewer systems shall
be an extension of an existing public system and designed in accordance with this design
manual.
10. Fire Hydrants and Water Mains: Adequate fire protection shall be required in accordance
with standards established by the City Engineer and the National Fire Protection Agency.
11. Street Name Signs: Street name signs shall be installed in the appropriate locations at each
street intersection in accordance with the local standards. See Roadway section for more
information.
12. Sidewalks and Pedestrian Walkways: Sidewalks shall be required on both sides of the street
and located within Right-of-Way. Pedestrian walkways shall be designed and installed per
section II E above
13. Sidewalks and crosswalks shall be constructed in accordance with the standards and
specifications as adopted by the City Engineer.
14. Mailboxes: Mailbox locations shall conform to U.S. Postal Service standards and not impede
traffic or pedestrian flow. See City details for placement.
15. Greenbelt: Greenbelts or landscaping screening may be required for the protection of
residential properties from adjacent major arterial streets, waterways, railroad rights of way
or other features. Subdivision plats shall show the location of any greenbelt areas.
16. Street Luminaires: Street luminaire shall be required to be installed at intersections
throughout the subdivision. Cost of conventional wood pole, luminaire, and service at
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intersections shall be the responsibility of the developer and installed to City Standards.
Other types or configuration for lighting shall be approved by the City Engineer prior to
installation.
17. Landscape and Sidewalk Placement: Landscaping and sidewalk placement is required
adjacent to arterial and collector streets. Within that tract the developer shall install
landscaping five feet (5') in depth with a sprinkler system and with grass and trees behind
the curb line and shall also install a six-foot (6') sidewalk. The developer may request the
City maintain this landscaping strip if constructed to City Standards and accepted by the City
for maintenance. The developer will include the requested area on a Preliminary Plat
submittal and if the City agrees to the Common Area Maintenance (CAM) areas, notes will
be required on the Final Plat along with Irrevocable restrictive covenants that provide for
funding of maintenance. The landscaping will be maintained by the city and funded
through a fee added to the water bill of each account within the development. Alternative
landscaping other than trees and grass may be approved by the city.
18. Pressure Irrigation System:
a. Use of the city's potable water supply as the primary source of irrigation water in all new
developments shall be prohibited. For purposes of this subsection, the term "new
development" means any new subdivision or ZDA, or any development of any parcel of
land of two (2) acres or larger that is not part of a subdivision or ZDA.
b. All new developments shall include an operating pressure irrigation system constructed to
city standards and approved by the City Engineer and the Twin Falls Canal Company.
Developers shall be required to connect to or construct a regional pump station. The
pressure irrigation system shall be operational prior to the first building permit being
issued for that station's service area.
c. The City Engineer may authorize in specific cases a variance from the requirement of a
pressure irrigation system, if not contrary to the public interest where, owing to special
conditions, a literal enforcement of the provisions of this subsection would result in
unnecessary hardship.
d. Special conditions may include, but are not limited to, small developments in terms of
acreage (<2 acres), or developments without viable access to irrigation water delivery.
e. Variances shall not be granted on the grounds of convenience or profit, but only where
strict application of the provisions of this title would result in unnecessary hardship.
f. The City Engineer shall not authorize a variance from the requirement of an operating
pressure irrigation system unless an alternate provision has been approved by the City
Engineer. Alternates may include, but shall not be limited to, required xeriscaping (i.e.,
landscaping in ways that do not require supplemental irrigation), payment of an in-lieu fee
equal to the estimated cost of construction of an operating pressure irrigation system
(including land acquisition), or some combination of these or other acceptable options.
g. One share of Twin Falls Canal Company water for each acre of property within the
subdivision shall be transferred to the city before recordation of the final plat for a public
system. For private systems the developer shall provide necessary documentation to
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verify the project has 1 share per acre of irrigation water prior to recordation of the final
plat.
19. Special Features: All other special features or items as represented during the approval
process.
11.05 DEDICATION OF STREETS:
11.05.1 Within a proposed subdivision arterial and collector streets as shown on a Master
Transportation Plan, shall be dedicated to the public in all cases; in general, all other streets
shall also be dedicated to public use. The dedication widths shall include their portion of the
street to behind the back of sidewalk at a minimum.
11.06 STREET LOCATION:
11.06.1 Street and road location shall conform to the following:
1. Street Location and Arrangements: All street locations shall conform to the Twin Falls
Master Transportation Plan where applicable. Collector type streets may, for aesthetic
reasons, curve, and wind in accordance with these standards, but such trafficways shall
maintain a grid type pattern as close to one-fourth (1/4) of a mile square.
2. Stub Streets: Where adjoining areas are not subdivided, the arrangement of streets in new
subdivisions shall be such that said streets extend to the boundary line of the tract to make
provisions for the future extension of said streets into adjacent areas. A vehicular nonaccess
reserve strip may be required and held in public ownership. Temporary cul-de-sacs shall be
required when longer than 150 feet and must be asphalted.
3. Relation to Topography: Streets shall be arranged in proper relation to topography so as to
result in usable lots, safe streets, and acceptable gradients.
4. Alleys: Alleys shall be provided in multiple dwelling or commercial subdivisions unless other
provisions are made for service access and off-street loading and parking. Dead end alleys
shall be prohibited in all cases.
5. Cul-De-Sac Streets: Cul-de-sac streets shall not be more than one thousand feet (1,000') in
length and shall terminate with an adequate turnaround having a minimum radius per the
current City of Twin Falls Standards.
6. Half Streets: Half streets shall be prohibited. The City Engineer may approve ½ plus 12’ (lip
of gutter or edge of asphalt) in locations where future phasing or adjoining properties will
develop their ½ in the future.
11.06.2 Emergency Access – Emergency Access Roadways are to be a minimum width of 24 feet with
a minimum centerline turning radius of 40 feet, unless otherwise approved by the Fire Chief.
Grades shall not exceed the maximum for street grades unless otherwise approved by the
Fire Chief and the City Engineer. It is intended that emergency access roads be open and
usable at all times. Where required, access to the roadway at each entrance shall be
controlled by an Emergency Access Control Gate, shall be posted “For Emergency Vehicles
Only’, and shall incorporate a Knox Box lock approved by the City of Twin Falls Fire
58 | Page
Department. Installation and maintenance of the gates shall be by the private development.
Other emergency access roadway requirements are as follow:
11.06.3 Temporary emergency access roads shall be surfaced to support a tandem axel loading of 40-
tons in all weather conditions and shall provide adequate roadside drainage.
11.06.4 Permanent emergency access roads shall be paved with a minimum of 2.5 inches of asphalt
concrete pavement on an engineered base and are to be provided with adequate roadside
drainage
11.06.5 Unless otherwise approved by the City Engineer, all improved emergency access roads shall
provide for vehicles to enter traffic nose-first.
11.06.6 Maintenance access: improved Maintenance Access or Vehicular Access Roads for
maintenance of the City owned sanitary sewer, stormwater, pressure irrigation, and culinary
water facilities and their related appurtenances are to be constructed to a minimum un-
encroached width of 12 feet clear of all lateral obstructions, 15 feet on horizontal curves,
structurally designed to support a tandem axle loading of 30 tons, with adequate roadside
drainage, and are not to exceed 8% in grade. Dead-end access roads in excess of 150 feet
shall require termination in a hammerhead, turnaround, or “Y” turn.
11.07 PRIVATE STREETS:
11.07.1 Private streets shall be prohibited except when allowed through the platting process. Private
streets will be owned and maintained by a property owners association, but public utilities
located therein will be owned and maintained by the City of Twin Falls. The public utilities
are Culinary Water, Wastewater, public storm drain system, public pressure irrigation system.
Streets that are collector or larger on our general ¼ mile grid shall be public to maintain
continuity.
11.07.2 Private Streets: The street width, sidewalks, trees, lawn, and other features shall be the same
as the requirements for the equivalent public street. Parking lot driveways or internal
circulation driveways within perpendicular parking for multi-family, commercial, or industrial
sites shall not be required to conform for private streets.
11.07.3 Gated private streets shall provide a means for vehicles to turn around if gates are closed. All
gates shall be “click to enter” per Fire Department standards unless otherwise approved by
the City Engineer. Maintenance of the gates shall be by the private development. Signs shall
be posted stating “Private Street, Not Maintained by the City”.
11.08 STREET SPECIFICATIONS:
11.08.1 Refer to the Roadway section of this document.
11.09 PEDESTRIAN WALKWAYS:
11.09.1 Right of way for pedestrian walkways in the middle of long blocks may be required where
necessary to obtain convenient pedestrian circulation to schools, parks, or shopping areas;
the pedestrian easement shall be 15’ wide and construction shall be per City standards and
specs. Cul-de-sacs will be connected to other adjacent streets with cul-de-sacs within the
proposed subdivision or existing subdivisions and to adjacent arterial or collector streets with
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paved pedestrian walkways at least fifteen feet (15') wide within fifteen-foot (15') tract. The
City Engineer has the right to amend this requirement on a case by case basis.
11.10 UTILITY AND DRAINAGE WAY EASEMENTS:
11.10.1 Unobstructed utility easements shall be provided along front lot lines. Additional easements
for rear lot lines and side lot lines when deemed necessary. Minimum front lot line
easements shall be 15’. All other easements are 15’ for a single pipe or 7.5’ from centerline
of all pipes if multiple pipes whichever is greater.
11.11 LOTS:
11.11.1 Lots shall conform to the following:
11.11.2 Zoning: The lot total area shall not be less than the requirements of any applicable zoning
district.
11.12 PLANTING STRIPS AND RESERVE STRIPS:
11.12.1 Planting strips and reserve strips shall conform to the following:
1. Planting Strips:
a. Planting strips shall be required to be placed next to incompatible features such as
highways, railroads, commercial or industrial uses to screen the view from residential
properties. Such screening shall be a minimum of twenty feet (20') wide and shall not be a
part of the normal street right of way or utility easement.
2. Reserve Strips:
a. Private Reserve Strips:
Privately held reserve strips controlling access to streets shall be prohibited.
b. Public Reserve Strips:
A one foot (1') reserve may be required to be placed along half streets which are within
the subdivision boundaries and shall be deeded in fee simple to the city for future street
widening.
11.13 RESTRICTIVE COVENANTS:
11.13.1 Restrictive covenants may be prepared and recorded as part of a subdivision. This is done to
provide protection to future property owners by establishing higher standards than required
under other regulations. The provisions within protective covenants are enforceable through
civil action and local governments shall not be required to enforce these provisions.
11.13.2 Subdivisions who wish to participate in Common Area Maintenance (CAM) program shall
have language within their CC&R’s that allows the City to charge a fee on the property
owners water bill for CAM areas depicted on their plans to be maintained by the City. This
language needs to be irrevocable and not subject to amendments by the HOA without City
approval. If the CC&R’s go away the maintenance of those CAM areas will be the
responsibility of the adjacent property owner.
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11.14 RIGHT OF WAY REQUIREMENTS:
11.14.1 Right of way widths per the following: An additional 12’ each side of R.O.W. will be required
on both collector and arterial roadways within 150’ (measured from PITC) of the intersection
for Acceleration/Deceleration or turn/bus lanes on all legs of an arterial/arterial or
arterial/collector intersection.
Commented \[TV35\]: see if there is a storm drainage
section
11.14.2 Street Specification Table:
Commented \[TV36\]: this should be located in the
Description Arterials Collectors Local
roadway section with language here that points them to the
roadway for development reqts
Right of Way minimum width 96 min. 78 ft min 50 ft min
104
desirable
Lip of Gutter to Limp of Gutter minimum 48 feet 30 feet min
width 33 feet desirable
Traffic, Parking and Bike Lanes minimum
width
Curbs minimum radii Collector street 30 feet 30 feet 10 feet min
20 feet desirable
Curb and Gutter 0.40% 0.40% 0.40%
Planter Strip min. width 8 feet 6 feet Not required
Design Speed min. 40 mph 35 mph 25 mph
Curve Radius 820 430 150
Min Tangent length 300 200 100
Cul-de-Sac R/W min radius Not allowed Not allowed 50 feet
Driveway maximum width 40 feet 40 feet 36 feet
Highest Street Classification Governs
11.15 RESPONSIBILITY FOR PLANS:
11.15.1 It shall be the responsibility of the subdivider of every proposed subdivision to have prepared
by a licensed engineer, a complete set of construction plans, including profiles, cross sections,
specifications, and other supporting data, for all required public streets, utilities, and other
facilities. Such construction plans shall be based on the approved preliminary plat and shall
be prepared in conjunction with the final plat. Construction plans are subject to approval by
the responsible public agencies. All construction plans shall be prepared in accordance with
the applicable public agencies' standards or specifications.
11.16 DRAINAGE:
11.16.1 All drainage facilities shall be designed to carry waters to the nearest practicable drainage
way and protect cut and fill slopes. A plan shall be submitted and approved by the
appropriate jurisdiction as a safe place to deposit such waters.
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11.17 ENGINEERS CERTIFICAITON REQUIREMENTS:
11.17.1 Subdivision Acceptance Standards
11.17.2 Testing Submittal standard
11.17.3 As-Built Submittal standard
11.17.4 Walk through process Guidelines for utility walks (June 2005 memo in doc folder)
11.17.5 Water and Sewer Modeling process (there is a memo but City may change process now)
11.17.6 Fees added to Subdivision Review Process might need to create the process (ensure fees
talked about in the final and pre-plat portions of this above)
11.17.7 Is the reconstruction to centerline discussed in the subdivision design standards ½ plus 12
and additional lane requirements (June 13, 2006 memo)
11.17.8 April 5, 2006, memo on design standards, is everything included above
11.17.9 Weeds dust and debris standards during construction
11.17.10 Parks design standards in Subdivision section. reference code.
11.17.11 In lieu process for parks, this may be incorporated into code or impact fee
11.17.12 Josh’s street section should discuss stopping sight distance located on the street specs of the
subdivision section of current code 10-12-3-4 & 10-12-3-6
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