CHAPTER 7
SENSITIVE AREAS
SENSITIVE AREAS
ARTICLE 7.1. SITE DISTURBANCES, STORMWATER CONTROL AND SHORELINE DEVELOPMENT
SECTION:
8.7.101: Applicability
8.7.102: Application And Information Requirements
8.7.103: Grading
8.7.104: Erosion And Sedimentation Control
8.7.105: Stormwater Detention And Conveyance
8.7.106: Stormwater Treatment
8.7.107: Groundwater And Springs
8.7.108: Down-Gradient Analysis
8.7.109: Geotechnical Analysis
8.7.110: Stream Protection Buffers
8.7.111: Shoreline Management Area
8.7.112: Hazards
8.7.113: Inspection
8.7.114: Maintenance
8.7.115: Prohibited Conduct
8.7.116: Administration
8.7.117: Risk Assessments
A. Permit Required: Except as exempted under subsection B of this section, a site disturbance permit shall be required for the following activities:
1. Construction of all new driveways, common driveways, private roads, or infrastructure authorized through the subdivision or conditional use permit process;
2. Conversion of roads from one use to another (such as a logging road to a private road, etc.) regardless of the level of improvement required on the road;
3. Excavation for the construction of structures;
4. Creation of a new commercial or industrial access or parking lot, or grading and paving of an existing commercial or industrial access or parking lot;
5. All other excavation and grading activity.
B. Exemptions: The following activities are exempt from the requirements of this article:
1. Mining, quarrying, excavating, processing, stockpiling of rock, sand, gravel, aggregate, or clay, to the extent approved for operation under applicable federal, state, Panhandle health district, and county regulations.
2. Agricultural practices in common local usage.
3. Activities governed by and subject to the Idaho forest practices act, title 38, chapter 13, Idaho Code (IFPA) which are solely for the purpose of enabling or engaging in a "forest practice", as defined in subsection 38-1303(1), Idaho Code.
4. Cemetery graves.
5. Emergency situations involving immediate danger to life or property, substantial fire hazards, or other public safety hazards as subsequently determined by the county, or during the period covered by an emergency declaration by the county.
6. Operation of a refuse disposal or landfill site which is constructed and operated under permits from appropriate federal, state and local agencies.
7. In any twelve (12) month period, excavation or placement of fill less than fifty (50) cubic yards in volume which is outside of any stream protection buffer or shoreline management area.
8. Private road or driveway maintenance where work is limited to the travelway, no cut or fill slopes are created, and no drainage features are created or modified.
9. Excavation of test holes for soil testing activities, provided that no access road will be created for test hole excavation, and the total excavation is less than fifty (50) cubic yards.
10. Grading, excavating and placement of fill on a site that has less than ten percent (10%) slope, and is more than five hundred feet (500') from surface water as defined by this article, and that results in disturbance of less than one-third (1/3) of the parcel, or sites over the Rathdrum Prairie Aquifer which are greater than five hundred feet (500') from surface water. This exemption shall not apply to commercial or industrial developments or for subdivision infrastructure development.
11. Grading, excavating, or placement of fill which is subject to the regulations and permitting authority of the U.S. army corps of engineers, the federal energy regulatory commission, the Idaho department of lands, the Idaho department of environmental quality, and/or the Idaho department of water resources. Grading activities that are related to such projects, but which are not subject to the aforementioned agencies' regulations or permitting authority, are not exempt.
12. Abatement of noxious weeds.
C. BMPs: Activities exempted pursuant to subsection B of this section shall employ BMPs to prevent sediment from leaving the site.
D. Utility Providers: Site disturbing activities conducted by utility providers shall be regulated as follows:
1. Major installation projects where utility service is regional in nature, e.g., intending to serve more than one subdivision or intending to upgrade existing service to multiple subdivisions, or commercial or industrial projects, shall comply with all applicable requirements of this article, unless otherwise exempt.
2. All other work conducted by utility providers shall be exempt from the requirements of this article, but shall use BMPs to prevent sediment from leaving the site. (Ord. 493, 6-9-2016; amd. Ord. 546, 10-17-2019)
A. Applications: All applications for a site disturbance permit shall be submitted to the department on a form provided by the department. At a minimum, the following information shall be required:
1. Property owner's name and applicant's name if different from the owner;
2. Legal description of property including parcel number;
3. A written description of the work to be done, including an estimate of the amount of earth to be moved;
4. A site plan, drawn to scale, including property boundaries, north arrow, adjacent roads, location of proposed work, and distances to property lines or prominent features of the land.
B. Site Inspection: Upon receipt of a completed application, the department will perform a site inspection to determine the risk categories as outlined in section 8.7.115 of this article. Using the outcome of risk assessment and the nature, location, and time of year of the project, the director shall determine whether the project is high, moderate or low risk.
C. Site Disturbance Plans: A site disturbance plan shall be required for all high and moderate risk sites. The required elements of site disturbance plans shall be outlined in the plan criteria manual adopted by the director.
1. Plans prepared by a design professional shall be required in the following circumstances:
a. Site disturbing activities governed by this article on high risk sites.
b. All commercial and industrial development except development by utility providers when not required under subsection 8.7.101(D) of this article.
c. Site disturbing activities conducted by utility providers, when required under subsection 8.7.101D of this article.
d. Subdivision infrastructure development.
2. Moderate risk sites. The following provisions shall apply to site disturbance plans in which preparation by a design professional is not required under paragraph 1 of this subsection:
a. Plans may be prepared by a design professional, contractor, or property owner.
b. Plans are not required to comply with the requirements of section 8.7.106 of this article.
3. The director may waive the submission of plans for minor improvements if the standards set forth in this article can be met by existing site conditions.
D. Interagency Coordination: The director may request comment from affected agencies where appropriate. Where coordinated permits are necessary, signoffs from permitting agencies or copies of other permits may be required. Permit authorities may include, but are not limited to:
1. Public highway agencies for work within public rights of way, including approach permits;
2. U.S. army corps of engineers;
3. Idaho department of lands for encroachments into navigable waters, logging activity under the IFPA, and surface mining activity;
4. U.S. environmental protection agency for site disturbing activity where an NPDES permit is required;
5. Coeur d'Alene Tribe for site disturbing activity within the boundaries of the Coeur d'Alene Indian Reservation; and
6. Idaho department of water resources for work within stream channels. (Ord. 493, 6-9-2016; amd. Ord. 546, 10-17-2019)
A. The slope of cut surfaces shall be no steeper than is safe for the intended use and shall be no steeper than two horizontal to one vertical (2:1), unless the design professional can demonstrate substantial evidence that steeper slopes are feasible, taking into account safety, stability, erosion control, revegetation, and overall water quality impacts. Subsurface drainage shall be provided as necessary for stability. All engineering reports are subject to review by the director.
B. Fill slopes shall be no steeper than is safe for the intended use and shall be no steeper than two horizontal to one vertical (2:1), unless the design professional can demonstrate substantial evidence that steeper slopes are feasible, taking into account safety, stability, erosion control, revegetation, and overall water quality impacts. Fill slopes shall not be constructed on natural slopes of forty percent (40%) (2.5 horizontal to 1 vertical) or steeper, without special treatment or design. In addition, the toe of fill slopes shall not be closer to the top of existing or planned downhill cut slopes than the height of that cut (e.g., if an 8 foot cut is planned, the toe of the uphill fill slope shall not be closer than 8 feet to the top of that cut), unless the design professional has demonstrated that comparable stability can be achieved with lesser setbacks.
C. Prior to placement of fill, the ground surface shall be prepared to receive fill by removing vegetation, topsoil, forest duff, and any other unsuitable material. The area to receive fill shall be scarified to provide a bond with the new fill. Fill shall not be placed until the area is prepared by constructing a level or slightly insloped toe bench into competent material at the base of the new fill. The director may waive the benching requirement for minor fills which are not intended to support a road, driveway, or structure. In high risk areas, the position, width, and configuration of the bench shall be determined by a design professional. Fill slopes and the transition zone into natural terrain shall be configured to a generally smooth, planar configuration so that runoff traverses the area as sheet flow and is not concentrated. Fill material shall be free of organic material except as may be determined by a design professional to be suitable. Roadway fills shall be placed in lifts and compacted to a minimum of ninety five percent (95%) of the maximum density as determined by the AASHTO T-99 or ASTM D-698 compaction procedure, or as specified in the design professional's report.
D. Except where roads or driveways cross property lines, the tops and toes of cut and fill slopes shall be set back from property boundaries one-half (1/2) of the height of the slope with a minimum of five feet (5') and a maximum of twenty feet (20'), unless the design professional has demonstrated that smaller setbacks provide a sufficient measure of safety and stability for activities which may occur on adjacent property.
E. Terracing shall be required on all cut or fill slopes which exceed fifty feet (50') in height. Spacing, width, and drainage requirements of the terrace(s) shall be determined by the design professional. (Ord. 493, 6-9-2016)
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