Chapter 19.83
EROSION CONTROL AND STORM DRAIN FACILITIES
Sections:
19.83.020 Application of standards.
19.83.040 Erosion and sediment control plan review.
19.83.050 Storm drainage facilities.
19.83.010 Purpose.
The standards and criteria for erosion and sediment control provide for the design of projects so as to minimize the harmful effects of stormwater runoff and the resultant inundation and erosion from projects, and to protect neighboring downstream and downslope properties from erosion and sediment impacts. [Ord. 2018-003 § 1; 2005 RLDC § 83.010.]
19.83.020 Application of standards.
A. These standards shall apply to any land division or land use application, including development and construction which would require any grading or filling on slopes that are 15 percent or greater or soils that are granitic in composition as mapped by the Natural Resources Conservation Service except when authorized or regulated by the Oregon Forest Practices Act.
B. An erosion and sediment control plan to prevent or mitigate possible hazards to life, property, or the natural environment shall be required.
C. Regardless of slope, for all land uses in the unincorporated areas of Josephine County:
1. Instances where fill is brought on site, or stockpiled, and said fill is in excess of 10 cubic yards, provisions shall be made to make sure runoff from that fill is maintained at the site. Best management practices to help control runoff shall be implemented, such as, but not limited to, straw bales or erosion control fabric.
2. There shall be no filling or grading on slopes in excess of 15 percent without a stormwater management plan signed by a registered, professional engineer, to prevent or mitigate runoff onto adjacent properties or waters of the state.
3. Berms, unless specified otherwise by code or condition, shall be set back from the property line, as measured from the base of the berm, a minimum distance equal to or greater than the required setback for a structure. Earthen berms shall be stabilized with ground cover. [Ord. 2018-003 § 1; Ord. 2017-001 § 1(7); 2005 RLDC § 83.020.]
19.83.030 Plan requirements.
A. Except as identified in subsections (C) and (D) of this section, an operation plan shall be submitted prior to any grading or filling on slopes 15 percent or greater, or on granitic soils in which the area disturbed exceeds 900 square feet, or on non-granitic soils when fill is brought on site or relocated on site in excess of 5,000 cubic yards.
B. The plan shall be prepared by a registered civil engineer, and shall provide the following information:
1. A statement of the land capabilities of the property on which the grading, filling, or clearing is to be performed, including soil series name, slope, gradients, runoff potential, soil depth, erosion potential, and natural drainage;
2. An accurate plot plan showing the exterior boundaries of the property on which the modification is to be performed, including the following:
a. Flow lines of surface waters onto and off of the site;
b. Existing and proposed contours at two-foot intervals;
c. Location, amount, and extent of cuts, fills, or contouring;
d. Existing and proposed drainage ways;
e. Building corner and street elevations for existing and proposed improvements;
f. Existing and proposed retaining walls;
g. The location and design of facilities for storage or conveyance of surface water runoff;
h. Estimates of existing and proposed runoff on the site;
3. The plan shall include an evaluation of the effects of projected runoff on adjacent properties and existing drainageways;
4. A list of equipment and methods to be employed in processing and disposing of soil and other material that is removed from the site, including the location of disposal sites;
5. The plan shall include information detailing the final ground cover, landscaping, erosion and drainage controls, and requirements for stable cut and fill slopes which will be based on detailed stability analysis. For the purposes of determining appropriate soil losses, the Natural Resources Conservation Service’s publication, Soil Interpretations for Oregon, shall be used.
C. On granitic soils with less than a three percent grade, a signed waiver from a registered engineer or licensed surveyor shall be allowed in lieu of the above required plan, provided said waiver documents no water or sediment will leave the property or enter a waterway.
D. In all cases where an operation plan is not required, the landowner shall ensure that Oregon Department of Environmental Quality construction best management practices are in place to minimize runoff onto adjacent properties and waterways. [Ord. 2018-003 § 1; 2005 RLDC § 83.030.]
19.83.040 Erosion and sediment control plan review.
The erosion and sediment control plan shall be submitted as part of the land division or land use application and shall be reviewed as part of the application. The Review Body, or the County Engineer where roads may be affected, shall review the plan and may recommend the installation or construction of improvements necessary to mitigate the impacts of the potential erosion and runoff. Be advised, the Oregon Department of Environmental Quality requires a permit for construction activities with one acre or more of disturbed soil or that are part of a larger common plan of development or sale and discharge to surface waters. [Ord. 2018-003 § 1; 2005 RLDC § 83.040.]
19.83.050 Storm drainage facilities.
Drainage facilities shall be provided for subdivisions, partitions, replats, or planned unit developments, and shall be connected directly to existing drainageways or storm sewers outside of the proposed land division that have an adequate capacity to accept drainage water from the subdivision, partition, replat, or planned unit development as provided below:
A. Design of drainage within the subdivision, partition, replat, or planned unit development shall be approved by the County Engineer, consistent with the County’s master storm drainage plan, and shall take into account the capacity and grade necessary to maintain unrestricted flow from areas draining through the subdivision, partition, replat, or planned unit development, and to allow extension of the system outside the subdivision, partition, replat, or planned unit development;
B. Drainage for the individual lots of the proposed subdivision, partition, replat, or planned unit development, and the proposed subdivision, partition, replat or planned unit development as a whole, shall be accomplished in such a manner so as to prevent the excessive flow of water across property lines, sidewalks, and other public rights-of-way;
C. When in the opinion of the County Engineer, land in a subdivision, partition, replat, or planned unit development which is or will be periodically subject to accumulations of surface water or is traversed by any watercourse, channel, stream, or creek, shall be required as a condition of approval to provide for adequate unrestricted drainage by the developer;
D. Provision for drainage shall be shown on a drainage plan both within and adjacent to the subdivision, partition, replat, or planned unit development. The plan shall show all easements and any improvements to be constructed;
E. Public improvements shall be approved by the Review Body as adequate for the drainage needs of the area. Where necessary, for protection of any needs, the Review Body may condition the tentative plan approval on the conveying of ownership of a drainage easement for drainage purposes to the County. [2005 RLDC § 83.050.]