All proposed subdivisions must comply with the following design and improvement standards where applicable. No waiver of any of these standards may be granted except pursuant to section 12-1-12 of this title.
A. Other Regulations: To the extent applicable, subdivision proposals shall comply with:
1. The following titles of this code (or those which supersede):
a. Any chapter of title 4, "Public Health And Safety";
b. Any chapter of title 8, "Sanitary Code";
c. Any chapter of title 9, "Building Regulations", with the recommendation or approval of the building official and fire official in an established district;
d. Any chapter of title 13, "Flood Control";
e. The adopted comprehensive plan.
2. Adopted Idaho transportation department standards, if the applicant seeks a new or expanded access onto a state highway.
B. Natural Feature Areas: Where practicable, the following specific areas regardless of location shall be left undeveloped and undisturbed:
1. Unique or fragile areas such as geologic features, floodways (as determined by title 13 of this code), and wetlands;
2. Areas of natural vegetation, including unique landscapes, large individual trees, and stands of trees. A plan for landscape protection, tree preservation, and tree introduction may be required;
3. Areas of significant value to wildlife;
4. Historically significant structures or sites; and
5. Natural drainage channels or watercourses.
C. Utilities: Any new utilities proposed or required for a subdivision shall be installed by the applicant unless such subdivision contains rural lots of two (2) acres or more. In such a subdivision, the applicant must provide easements for future utilities. Such utilities must include underground service connections for (to) each platted lot. Service feeder lines into the subdivision from the exterior utility point of feed shall be installed underground, beginning at the subdivision boundary. Utilities can be overhead or underground to the subdivision boundary.
D. Water Supply:
1. General Requirements:
a. All domestic water sources shall meet state and federal standards for drinking water, wells, separation from sewage disposal systems and any other related requirements.
b. Fire protection systems shall meet local fire code requirements.
c. All abandoned wells shall be sealed to prevent contamination of groundwater.
d. The requirements of Idaho Code section 42-111 for domestic water limits and section 50-1334 for subdivision water systems shall be satisfied.
e. Domestic water shall be available in sufficient quantity to meet foreseeable demands. Where insufficient data is available to verify water quantity, an on site test well in the area of the proposed use shall be required.
2. Central Water Systems:
a. Central or community water systems shall be required for subdivisions where any lot is one acre or less in size or in any subdivision located in an R-2 zone.
b. The central water system requirement shall be met by establishment of one of the following:
(1) A water district formed under state law and acceptable to the Idaho department of environmental quality ("DEQ"). A copy of the final DEQ approval shall be provided in writing to the county.
(2) A private user's agreement addressing the operation, maintenance and ongoing monitoring of the central water system. A copy of the final, signed agreement shall be provided in writing to the county.
c. If deemed necessary by the county engineer and/or the applicable fire district, circular or looped water supply systems may be required.
d. The board reserves the option to require central water systems for subdivisions where necessary to provide for the public health, safety or general welfare.
e. Central or community water systems shall be designed by a registered engineer in Idaho and shall comply with the current requirements of Idaho department of environmental quality drinking water distribution checklist.
f. Construction of central or community water systems shall be observed by a registered engineer in Idaho to the extent necessary for the observing engineer to make a written statement that the water system was constructed substantially as shown on the drawings.
3. Irrigation And Domestic System Requirements:
a. Existing on site surface and ground water rights shall be used for existing and proposed on site agricultural uses and domestic and landscape needs before additional domestic rights are sought.
b. Agricultural and domestic water delivery systems shall not be intermingled.
c. All subdivisions shall satisfy the requirements of Idaho Code section 31-3805 for irrigation water delivery.
d. Where surface water irrigation rights are available, all subdivisions containing buildable lots less than one acre in size shall provide underground, pressurized irrigation water to every lot. The pressurized irrigation system shall be constructed and installed at the same time as the domestic water lines, but it shall not necessarily be in the same trench.
E. Sewage Disposal:
1. All sewage disposal systems shall meet DEQ standards as administered by the Southwest district health department ("SWDH") and as set forth in the Idaho Code.
2. A sewage district or other entity acceptable to DEQ shall be organized for the operation, maintenance and ongoing monitoring of any central sewage system. A copy of the final DEQ approval shall be provided in writing to the county.
F. Public And Private Road Improvements:
1. Road Classification: Road classifications shall be determined jointly by the administrator, county engineer and Gem County road and bridge department, based upon board approved criteria.
2. Road Location: Roads shall be located in accordance with the following guidelines:
a. Subdivision roads and right of way widths shall conform to the Gem County functional classification map, as adopted by the board. Minimum right of way widths for roads not identified on the functional classification map shall be determined per subsection F1 of this section.
b. Frontage roads, landscaping or other design devices to screen or separate traffic shall be required where a subdivision abuts or contains an arterial or major thoroughfare for adequate protection of residential property and to separate through traffic from local traffic.
c. Roads for industrial and commercial subdivisions and accessory parking shall be planned to connect with arterial roads so as not to generate traffic on local or minor roads.
d. Alleys shall be provided in multiple dwelling, commercial or industrial subdivisions for service access or off road loading. Sharp turns or dead end alleys are prohibited.
e. Culverts or bridges shall be provided and installed by the applicant where drainage channels intersect any road rights of way. Culverts shall, at a minimum, extend across the entire width of the road and shoulder.
f. Roads shall be complementary to existing road patterns and tie into the existing system where stub roads indicate that intent. New stub roads and/or pedestrian walkways to adjacent, undeveloped parcels will be required to ensure interconnectivity and make provisions for the future extension of said roads into adjacent areas. Roads that are a continuation of established roads shall be aligned so that the centerlines coincide within no more than ten feet (10') of each other.
g. Reserve or no access strips controlling access to public roads shall be required along designated arterials and permitted along designated collectors provided that the control and disposition of that land is placed within the jurisdiction but not ownership of the county under conditions specified and shown on the final plat. Such strip may be used as the utility easement if appropriate.
h. Underground conduit for utilities shall be coordinated with all utility providers before they are completed to prevent future disruption for installation and to determine easement locations.
3. Public Road Dedication: Local, collector and arterial roads within a proposed subdivision shall be offered for dedication to the public. Dedication or other provision for future access to surrounding public land may be required. Private roads shall not be allowed where there is a need for public access to adjacent lands.
If the requirement by a governmental entity to dedicate public right of way reduces the property to be developed in such a manner that lot layout, in minimum sizes as required by that zone, cannot be accomplished without creating one substandard sized lot, then one such lot may be created as long as its size is not less than eighty percent (80%) of the size required in that zone. Such lot shall not be considered substandard and will be considered to meet minimum lot size for purposes of development.
a. Roads shall be arranged in proper relation to topography so as to result in usable lots, safe roads and acceptable gradients.
b. Local roads shall be arranged to discourage through traffic.
c. Dead end roads are prohibited. Stub roads with a temporary cul-de-sac may be permitted in anticipation of a future through road. When a temporary cul-de-sac is removed by extension of the road, it shall be the responsibility of the party or parties extending said road to relocate the curbs, gutters, sidewalk and road, if any, to county standards. It shall also be the responsibility of said parties to restore that portion of lot or lots affected by said extension to a reasonable and usable condition.
d. Cul-de-sac roads shall be discouraged. However, when topography or planning considerations dictate their use, cul-de- sacs shall:
(1) Include a right of way measuring sixty feet (60') in radius at the terminus;
(2) If offered for dedication to the county, meet county road specifications and include an entirely paved terminus measuring fifty feet (50') in radius;
(3) Have the length be designed in accordance with the fire district specifications, but no more than one thousand feet (1,000') without a secondary means of vehicular access provided. All designs shall require approval of the local fire authority and additional conditions may be applied.
The board shall have the explicit option of accepting or rejecting the road for dedication to the county.
e. Half roads shall be prohibited except where satisfactory assurance for dedication of the other half is provided. If a half road right of way is accepted, the road section shall be designed for two-way traffic and include all required drainage facilities for said road.
f. If the requirement to dedicate public right of way on roads classified as collector or arterial reduces the property to be developed in such a manner that lot layout, in sizes as required by that zone, cannot be accomplished without creating one substandard sized lot, then one such lot may be created as long as its size is not less than eighty percent (80%) of the size required in that zone. Such lot shall not be considered substandard and will be considered to meet the minimum lot size for purposes of development.
4. Private Roads Or Drives:
a. If a private drive serving two (2) dwellings is required, the developer/subdivider will have responsibility for construction of the drive as a subdivision improvement.
b. Private roads proposed to serve new subdivisions will only be authorized if:
(1) The proposed subdivision is not adjacent to any other parcel that may be subdivided to the minimum lot size of the existing zone and which requires vehicular access through the proposed subdivision in the future. This must be demonstrated through a legally recognized tool (e.g., a permanent conservation easement) or through topography and/or other natural barriers. If the parcel adjacent to the proposed subdivision cannot be subdivided in such a manner as to create more than a cumulative total of ten (10) building lots or parcels on the same private road (which includes all existing and potential building lots or parcels), then a private road may be authorized to serve the new subdivision. (The intent of this section is to preserve a potential access corridor and not to require the improvement of said corridor if a subdivision does not create the need for the road.)
c. If the above criteria is met, then the following shall also apply before a private road will be authorized:
(1) The proposed subdivision does not have legal frontage on a public road and utilizes an existing private road or road easement for access. Under this circumstance, the subdivider shall obtain written consent from the road easement grantor approving of the proposed subdivision and expanded use of the easement. In addition, the subdivider must provide an updated maintenance agreement or user's association document with the subdivision application that clearly demonstrates the private road will be adequately maintained; or
(2) The proposed subdivision has legal frontage on a public road and cannot be subdivided in such a manner as to create more than a cumulative total of ten (10) building lots or parcels on the same private road (which includes all existing and potential building lots or parcels).
d. If a private road is authorized under the above criteria, the following conditions shall apply:
(1) A private road name application must be submitted at the time of subdivision application (for new private roads);
(2) The private road may serve no more than ten (10) building parcels and/or lots;
(3) If the private road is more than one thousand feet (1,000') in length (measured from the right of way line of the connecting public road to the center of the turnaround or other approved terminus), a secondary emergency access must be provided to the subdivision. All designs shall require approval of the local fire authority and additional conditions may be applied.
(4) The road shall be constructed by the developer/subdivider to comply with the type B private road standards adopted in the zoning ordinance. If an existing, nonconforming private road is being utilized, the developer shall bring said road into conformance with type B standards at the time of subdivision construction;
(5) Private roads on properties inside an area of city impact shall be constructed to the city's public street standard for an urban local road and serves development with a maximum density of three (3) dwelling units per acre;
(6) The private road shall connect directly to an existing public road; and
(7) No new private road or extension of an existing private road shall alter the alignment of any portion of said road more than forty five degrees (45°).
G. Intersection Location And Specifications: Intersections shall conform to the following:
1. No more than two (2) roads shall intersect at one point.
2. Local road centerlines shall be offset by at least one hundred twenty five feet (125').
3. Roads shall intersect at ninety degrees (90°) or as closely thereto as possible, and in no case shall roads intersect at less than seventy degrees (70°).
H. Road Specifications: The following road specifications, in addition to the local highway technical assistance council (LHTAC) and the Idaho state public works code (ISPWC) requirements, adopted herein by reference, shall apply:
1. Road Construction: Road construction shall comply with the current adopted standards of the Gem County road and bridge department. If any road within the area of city impact is designed to connect with any road within any city limits, such road shall meet the design requirements of that city.
2. Road Names: All new road names shall be approved by a committee formed by the board for reviewing road names. Proposed road names shall not duplicate or be sufficiently similar in sound or spelling to cause confusion with existing road names. Road names on new roads that are aligned with existing roads shall have the same name as the existing roads, where the committee determines that it is in the best interest of the public health, safety, and welfare. Road name signs and all other traffic control signs or devices as required by the board shall be installed by the applicant.
3. Road Design: All roads shall be designed by a licensed professional civil engineer. The plans and specifications for such roads shall be approved by the county prior to acceptance of the final plat. The design engineer shall certify that the road construction meets the applicable specifications prior to the county accepting new road dedication.
I. Unsuitable Land: Land with conditions that may be detrimental to the health, safety or general welfare of existing or future residents because of potential hazards such as landslides, subsidence, high water table, high pressure gas lines, power transmission lines, or other features with severe development limitations shall not be subdivided for building or residential purposes unless the hazards or other features are eliminated by lawful permit or overcome by approved design and construction plans.
J. Applicant Or Landowner: If the applicant or landowner with respect to an application for a subdivision under this title is the state of Idaho, or any agency, board, department, institution, or district thereof, the commission or the board, in addition to all other applicable standards and criteria hereunder, shall take into account the plans and needs of the state, or any agency, board, department, institution or district thereof, as required by Idaho Code section 67-6528.
K. Lots:
1. Building Site: Each lot shall contain a satisfactory building site that is properly related to topography.
2. Corner Lots: Corner lots shall be a sufficient area without obstructive landscaping to provide acceptable visibility for traffic safety.
3. Access: Each lot shall have access to an internal road or drive, where practicable.
4. Calculation Of Lot Area: Calculation of lot area shall not include land that is below the "natural or ordinary high water mark" of navigable streams (as defined by Idaho Code section 36-1601), and therefore subject to the public trust doctrine.
5. Large Lots: If the average lot size in a residential subdivision is more than double the minimum acreage required for a residential zone, equal to or exceeds the minimum acreage required in the residential/agricultural zone (A-2 or A-3) or is within an area of city impact, applicants may be required to arrange lots in anticipation of future resubdivision and provide for future roads where necessary to serve potential lots.
6. Compliance With Regulations: Lot sizes, uses and the location of uses shall satisfy any zoning regulations and other applicable sections of this code.
7. Division By Road Or Other Lot: No single lot shall be divided by a road, existing right of way or other lot.
8. Division By Boundary Line: No single lot shall be divided by a municipal or county boundary line.
9. Distance From Power Lines: No residential building or structure for human habitation shall be located within one hundred fifty feet (150') of the centerline of a power transmission line.
10. Flag Lots: Flag lots will be allowed under the following conditions:
a. The pole portion of the lot which touches the public or private access is at least forty feet (40') in width on lots forty (40) acres or less in size, or at least sixty feet (60') in width on lots more than forty (40) acres in size or at least fifty feet (50') in width on any lot within the Emmett area of city impact.
b. The length of the pole portion of the lot does not exceed fire department regulations.
c. All other portions of this code apply to the lot bulk and placement.
d. Required setbacks shall be measured from the nonpole portion of the lot.
L. Remainder Parcels/Lots: If subdividing land under one deed in phases, all land described by that deed shall be included in the boundaries of the preliminary plat and all land included in the phase being developed will be included in the final plat. Any land within the plat reserved for future division shall be platted as lots that meet the minimum dimensional standards for the zone in which they are located, and meet all other applicable land use ordinances.
M. Blocks:
1. The length, widths, and shapes of blocks shall be determined with due regard to:
a. Provision of adequate building sites suitable to the special needs of the type of use contemplated including the base district requirements as to property sizes and dimensions.
b. Avoiding double front lots. If unavoidable, one of the frontages shall be restricted from vehicular access.
c. Needs for convenient access, circulation, control, and safety of road traffic. The number of intersecting roads with arterials of all classes shall be held to a minimum.
d. The limitations and opportunities of topography.
2. Any residential block length greater than one thousand two hundred feet (1,200') in length shall provide the necessary mitigation as required by the fire authority having jurisdiction. Emergency access mitigation options shall be identified and presented in writing at the time of subdivision application. Final mitigation requirements shall be determined during the board review and made conditions of approval.
3. Pedestrian access rights of way not less than ten feet (10') wide may be required for walkways through or across a block when deemed desirable to provide circulation, or access to schools, playgrounds, shopping centers, transportation, and other community facilities. Said access right of way shall be a separate platted lot.
The board may review and modify block sizes.
N. Utilities: The applicant shall:
1. Grant a public and private utility easement of an adequate width (typically 5 to 10 feet) to comply with all utility companies and other potential easement users in all required locations on the plat (see subsection R of this section for additional easement requirements); and
2. Install utilities prior to road surfacing; and
3. Obtain services of a qualified testing firm to pressure test all central or community water and sewer main lines and TV inspect all sewer main lines. Paving of roads will not be done until testing and inspection of the water and sewer main lines show they meet requirements of the "Idaho Standards For Public Works Construction".
O. Drainage:
1. The applicant shall provide suitable drainage facilities for any surface runoff from within or upstream of the subdivision. On site natural drainage channels, gullies, ditches and ravines shall be used whenever possible. To avoid soil erosion and manage nutrients, sediment catchment basins may be required. The applicant shall follow the stormwater, erosion and drainage requirements of section 11-6-11 of this code.
2. Where a subdivision contains a stream, watercourse, drainageway, channel or ditch, an easement shall be provided adequate to contain that watercourse and any further width necessary for maintenance or reconstruction.
3. Drainage systems shall not discharge into any sanitary sewer facility.
4. When the proposed subdivision or any part thereof falls within the boundaries of a mosquito abatement district, all drainage plans and systems shall follow the guidelines of such district.
P. Park Or School Site Dedication: Based on a recommendation regarding the suitability of the site from the recreation or school district, an applicant may be required to provide either land or a financial contribution or both for playgrounds, recreation space or a school site based on a rationally related formula determined by a resolution or ordinance of the board.
Q. Public Access Easements: The board may require an access easement to publicly administered land, streams, rivers, lakes and reservoirs. An applicant shall clearly delineate for the public the location of any access easement by appropriate signage and rail fencing, and create an obligation by the homeowners' or lot owners' association to maintain unrestricted passage by the public. The board may require an easement for a future trail system connection.
R. Easements: It shall be the responsibility of the applicant to provide on the final plat such easements required for utilities, drainage, access, irrigation, waterways or other public facilities. The widths of such easements shall be adequate for the facilities planned or proposed. In subdivisions with lots of one acre or smaller, utility easements will be provided on all lot lines. In subdivisions with lots of over an acre utility easements may be shown along lot lines required to install proposed utilities. Prior to filing the final plat, the applicant shall have submitted the plat to the person(s) authorized to perform plat review for the utility interests. Prior to final plat review by the administrator, a letter shall have been received from the interested utilities signifying that easements shown on the plat are complete and satisfactory for utility purposes. Where a subdivision is transversed by a watercourse, appropriate easements shall be provided.
S. Design Of Subdivisions Within Or Adjacent To Lands Zoned A-1:
1. The subdivision shall be designed and residential structures located to minimize the impact on agricultural land, farming operations, and sensitive environmental features. The board shall consider, without limitation, the following design criteria:
a. Locating residential structures as far from neighboring agricultural lands as possible;
b. Grouping land uses as much as practical, such that agricultural lands abut neighboring agricultural lands and residential structures are located contiguous with other residential uses;
c. Locating structures on the least productive agricultural land and in such a manner as to have little impact on any environmental, agricultural or open space resources; and
d. Placing residential structures nearest to utilities and roads to minimize the amount of construction and the loss of agricultural land. (Ord. 2009-06, 9-28-2009)