TROUTDALE DEVELOPMENT CODE

5.600 EROSION CONTROL AND WATER QUALITY STANDARDS ER

5.610 Purpose. The purpose of these standards is to reduce the amount of sediment and pollutants reaching the public storm and surface water system resulting from development, construction, grading, excavating, clearing, and any other activity which accelerates erosion or increases water pollution. The objective is to control erosion and pollution at its source in order to maintain and improve water quality and reduce downstream impacts.

5.611 Applicability. An erosion control and mitigation plan shall be required and approved by the Director under any of the following circumstances:

A. Prior to final plat approval for any subdivision, in accordance with Chapter 7.100.

B. Prior to Site Orientation and Design Review, in accordance with Chapter 8.050.

C. Prior to approval of any building or grading permit that results in:

1. Disturbance of 1,000 square feet or more of land surface area.

2. Land or native vegetation disturbance within 50 horizontal feet of top of bank of any wetland, stream or river.

3. Disturbance of land or vegetation affecting 500 square feet or more of land area on slopes of 25 percent or greater.

D. Farming activities are exempt from the provisions of Section 5.611.C.1, provided that the specific land area has been cultivated within the last three years.

E. Upon a finding that visible or measurable erosion has entered, or is likely to enter, the public storm and surface water system. As used in this section, "visible or measurable erosion" shall include the following:

1. Depositions of soil or sediment exceeding one cubic foot in volume on a public or private street, adjacent property, or into the surface water management system either by direct deposit, dropping, discharge or as a result of erosion.

2. Flows of water over bare soils, turbid or sediment laden flows, or evidence of on-site erosion such as rivulets or bare soil slopes, where the flow of water is not filtered or captured on the site.

3. Earth slides, mud flows, earth sloughing, or other earth movement which leaves the property of origin.

F. Single Family Lot Exemption - Standard Erosion Control Plan.

Standard Erosion Control Plan Option. In lieu of compliance with TDC 5.614 the developer may choose to follow the requirements of the Standard Erosion Control Plan, approved by the Planning Commission and on file in the Community Development Department in the following circumstances:

a. The lot is 20,000 square feet or less.

b. No portion of the lot exceeds 5% slope.

Nothing in this section shall relieve any person from the obligation to comply with the regulations or permits of any federal, state, or local authority. See also Troutdale City Code, Chapter 12.09.

5.612 Approval Standards. The Director shall make the following affirmative findings prior to approval of an erosion control plan:

A. The project has been designed to minimize disturbance of natural topography, native vegetation and soils, consistent with applicable provisions of Sections 4.300 (Hillside Preservation) and 4.600 (Flood Hazard).

B. The site design maximizes the preservation of healthy trees, understory shrubs and ground cover.

C. The plan complies with the applicable technical guidelines, as determined by the Public Works Director. In the case of erosion control standards, the City of Gresham Erosion Control Plans Technical Guidance Handbook, April 1991 Edition, shall be the recognized authority. In the case of water quality facilities, the Stormwater Management Manual for the Puget Sound Basin, February 1992 Edition, shall be the recognized authority.

5.613 Erosion Control Plan Submission Requirements. The required erosion control plan shall include a narrative description and scaled drawings which address:

A. The physical characteristics of the site, including a map of existing topography at 2 foot contour intervals, the location of water areas, and a narrative description of soil characteristics. The requirement for a 2 foot contour map may be waived by the Director where this information is not readily available, and erosion potential is minor.

B. The nature of the proposed development, including any phasing plans, which may affect soils or create soil erosion. Areas of excavation, grubbing, clearing, stockpiling, or vegetation removal shall be specifically identified.

C. Specific erosion control measures and practices to be used to demonstrate compliance with Section 5.614.

5.614 Erosion Control Plan Standards. In addition to compliance with relevant portions of the City's Hillside and Flood Hazard Overlay Districts, the required Erosion Control Plan shall comply with the following standards:

A. Control Measures. Specific methods of soil erosion and sediment control shall be used during construction to minimize visible and measurable erosion. In no case shall soil erosion and sediment transport from the site exceed the rate of one ton per acre per year. These methods shall include all of the following:

1. The land area to be grubbed, stripped, used for temporary placement of soil, or to otherwise expose soil shall be confined to the immediate construction site only.

2. The duration of exposure of soils shall be kept to a minimum during construction. Exposed soils shall be covered by mulch, sheeting, temporary seeding or other suitable material following grading or construction, until soils are stabilized. During the rainy season (November through May), soils shall not be exposed for more than seven consecutive (7) days. All disturbed land areas which will remain unworked for 21 days or more during construction, shall be mulched and seeded.

3. During construction, runoff from the site shall be controlled, and increased runoff and sediment resulting from soil disturbance shall be retained on-site. Temporary diversions, sediment basins, barriers, check dams, or other methods shall be provided as necessary to hold sediment and runoff.

4. A stabilized pad of gravel shall be constructed and maintained at all entrances and exits to the construction site. The stabilized gravel pad shall be the only allowable entrance or exit to the site.

5. Topsoil removal for development shall be stockpiled and reused on-site to the degree necessary to restore disturbed areas to their original or enhanced condition, or to assure a minimum of six inches of stable topsoil for re-vegetation. Additional soil shall be provided if necessary to support re-vegetation.

6. The removal of all sediments which are carried into the streets, or on to adjacent property, are the responsibility of the developer. The applicant shall be responsible for cleaning and repairing streets, catch basins, and adjacent properties, where such properties are affected by sediments or mud. In no case shall sediments be washed into storm drains, ditches, drainage ways, streams, or wetlands. See also Chapter 12.09 of the Troutdale Municipal Code, related to public facilities.

7. Any other relevant provision of the April 1991 edition of the City of Gresham Erosion Control Plans Technical Guidance Handbook, required by the Director.

B. Restoration of Vegetation. In addition to compliance with native vegetation removal and enhancement provisions of Sections 4.300 and 4.600 of this code, the developer shall be responsible for re-vegetating public and private open spaces, utility easements, and undeveloped rights-of-way in accordance with an approved Schedule of Installation.

1. If the vegetation existing prior to site development is non-native or invasive, it shall be replaced with native or non-invasive plant species.

2. Temporary measures used for initial erosion control shall not be left in place permanently.

3. Work areas on the immediate site shall be carefully identified and marked to reduce potential damage to trees and vegetation.

4. Trees shall not be used as anchors for stabilizing working equipment.

5. During clearing operations, trees and vegetation shall not be permitted to fall or be placed outside the work area.

6. In areas designated for selective cutting or clearing, care in falling and removing trees and brush shall be taken to avoid injuring trees and shrubs to be left in place.

7. Stockpiling of soil, or soil mixed with vegetation, shall not be permitted on a permanent basis.

C. Schedule of Installation. A schedule of planned erosion control and re-vegetation measures shall be provided, which sets forth the progress of construction activities, and mitigating erosion control measures.

D. Responsible Person. The developer shall designate a specific person to be responsible for carrying out the Erosion Control Plan.

E. Reference Authority. The April 1991 edition of the City of Gresham Erosion Control Plans Technical Guidance Handbook shall be the primary guide for the City of Troutdale in establishing and reviewing erosion control techniques, methods and requirements. The Director and Public Works Director may also develop regulations and procedures in accordance with the Handbook to implement erosion control measures as needed.

5.615 Plan Implementation Requirements. An approved Erosion Control Plan shall be implemented and maintained as follows:

A. Plan Approval Required Prior to Clearing or Grading. No grading, clearing or excavation of land requiring an Erosion Control Plan shall be undertaken prior to approval of the Erosion Control Plan. Erosion control measures shall be installed prior to any stripping or excavation work.

B. Implementation. The developer shall implement the measures and construct facilities contained in the approved Erosion Control Plan in a timely manner.

1. During active construction, the developer shall inspect erosion control measures daily during rainy periods. In all cases, the developer shall be responsible for maintenance, adjustment, repair and replacement of erosion control measures to ensure that they are functioning properly without interruption.

2. Eroded sediment shall be removed immediately from pavement surfaces, off-site areas, and from the surface water management system, including storm drainage inlets, ditches and culverts. See also Troutdale Municipal Code, Chapter 12.09. In the event that sediment is inadvertently deposited in a wetland or stream, the developer shall immediately contact the Director and coordinate remedial actions with the City.

3. Water containing sediment shall not be flushed into the surface water management system, wetlands or streams without first passing through an approved sediment filtering facility or device.

4. When required by the Director, the developer shall maintain written records of all site inspections of erosion control measures which shall be provided to the Director upon request.

5. In addition, the developer shall call for City inspection, prior to the foundation inspection for any building, to certify that erosion control measures are installed in accordance with the erosion control plan.

C. Dust Control. Troutdale is especially susceptible to wind erosion. Therefore, the Director may require that additional dust control measures be included in the Erosion Control Plan. Such control measures may include, but are not limited to, the following:

1. Sprinkling access and haul roads and other exposed dust producing areas with water.

2. Applying dust palliatives to access and haul roads.

3. Establishing temporary vegetative cover.

4. Placing wood chips, gravel or other effective mulches on vehicle and pedestrian use areas.

5. Maintaining the proper moisture condition on all fill surfaces.

6. Pre-wetting cut and fill surface areas.

7. Using covered haul equipment.

D. Correction of Ineffective Measures. If the facilities and techniques approved in the Erosion Control Plan are not effective or sufficient to meet the purpose of this section, based on an on-site inspection, the Director may require a revised plan.

1. The revised Erosion Control Plan shall be provided within 5 working days of written notification by the Director.

2. The developer shall implement fully the revised plan within 5 working days of approval by the Director.

3. In cases where serious erosion is occurring, the Director may require the developer to install interim control measures immediately, before submittal of the revised Erosion Control Plan.

E. Additional Standards. The following additional standards shall apply:

1. Construction between stream banks shall be prohibited, unless absolutely necessary to construct required public facilities.

2. Pollutants such as fuels, lubricants, bitumens, raw sewage, and other harmful materials shall not be discharged into or near rivers, streams, or impoundments, and shall be properly stored and disposed.

3. Discharge of water into a stream, wetland or impoundment shall not result in altering the temperature of the water body enough to affect aquatic life.

4. All sediment-laden water from construction operations shall be routed through stilling basins, filtered, or otherwise treated to reduce the sediment load.

F. Storage. All erodible or toxic materials delivered to the job site shall be covered and protected from the weather and stored according to appropriate health and safety guidelines.

1. Such materials shall not be exposed during storage.

2. Waste material, rinsing fluids, and other such material shall be disposed of in such manner that pollution of groundwater, surface water, or air does not occur.

3. In no case shall toxic materials be dumped into drainage ways or onto land.

G. Contaminated Soils. Where the construction process reveals soils contaminated with hazardous materials or chemicals, the Contractor shall stop work immediately; ensure that no contaminated material is hauled from the site; remove the work force from the contaminated area; leave all machinery and equipment; secure the area from access by the public until such time as a mitigation team has relieved them of that responsibility; notify the City of the situation upon its discovery; and prohibit employees who may have come in contact with the contaminated material from leaving the site until released by the Emergency Response Team.

H. Duration of Maintenance. Continuing maintenance after development pursuant to the Erosion Control Plan, including re-vegetation of all graded areas, shall be the responsibility of the developer, subsequent developers or property owners.

1. Erosion control measures shall be maintained during construction and for one year after development is completed.

2. The Director may, upon a finding that soils are completely stabilized, reduce this period.

5.616 Special Water Quality Treatment Facilities. Beaver Creek and the Sandy and Columbia Rivers are vitally important to Troutdale's recreational-based economy and to the quality of life of Troutdale residents. Special water quality detention and treatment facilities may be required for major developments draining to Beaver Creek, or the Sandy or Columbia Rivers, designed in accordance with the Stormwater Management Manual for the Puget Sound Basin (Washington Department of Ecology, February 1992).

A. Applicability. The Director shall require water quality treatment or detention facilities for developments which qualify under any of the following:

1. The development involves 10 acres or more.

2. The development occupies one acre or more of steep slope or constrained slope area.

3. The development will cause degradation of water quality in the receiving stream without detention or treatment.

4. The development involves paved parking areas (exclusive of single family and two-family residences), fuel storage or dispensing areas, vehicle wash areas, or vehicle maintenance or dismantling areas.

B. Responsibility and Treatment Options. Water quality facilities for major developments shall be required for purposes of minimizing water quality impacts on Beaver Creek and the Sandy River, prior to deposition into natural drainage ways.

1. Water quality facilities shall be designed and constructed by the developer, to ensure that stormwater runoff is treated on site, prior to discharge.

2. Treatment may include infiltration devices, grassy swales, treatment ponds or other methods approved by the City, consistent with the Stormwater Management Manual for the Puget Sound Basin, February 1992.

C. Placement of Water Quality Facilities. Placement of water quality facilities shall be limited as follows:

1. The water quality facilities shall not be constructed within an existing or created wetlands unless a mitigation plan is approved by the City and the Oregon Division of State Lands.

2. The water quality facility shall not be placed on land with slopes of 15% or greater, within 50 feet of the top of the bank of a stream, or within a defined floodway area.

3. The water quality facility may be constructed within the 100 year floodplain, provided that the area is (a) outside the area covered by the 25-year flood event, and (b) the water quality facility effectively and exclusively uses native plant species.

4. Where the approval authority determines that a more efficient and effective regional site exists within the sub-basin, the water quality facility may be constructed off-site.

D. Water Quality Facility Standards. The design and functions of required water quality control facilities shall be determined based on the recommendations of the Stormwater Management Manual for the Puget Sound Basin.

1. The preliminary subdivision plat, site plan, or permit application shall include plans and a certification prepared by a professional engineer registered in Oregon that the proposed stormwater quality control facilities have been designed in accordance with the Stormwater Management Manual for the Puget Sound Basin.

2. The plan shall specifically consider source control of pollution (oil and water separators), runoff treatment, streambank erosion control, wetland impacts, impacts on water quality sensitive areas, and off-site analysis and mitigation (Minimum Requirements 1-14, pp. I-2-5 through I-2-14).

3. A long-term (20-year) operation and maintenance plan shall be required. This plan shall document how and by whom the water quality facility will be maintained.

4. If the water quality facility is dedicated to the City, maintenance of the facility shall be the responsibility of the developer for at least two years after the facility has been constructed and approved by the City.

If the facility is not dedicated to the City, then it shall be the continuing responsibility of the developer.

5. In all cases, runoff from impervious areas used for repair, cleaning, refueling, storing or servicing of vehicles and machinery shall be treated on site to remove oil, grease and other chemicals.

5.617 Security. Except as provided by Section 5.617.B, after an Erosion Control Plan or Water Quality Facility is approved by the Director and prior to construction or grading, the applicant shall provide a performance bond or other financial guarantee in the amount of 120% of the value of the erosion control and water quality measures necessary to stabilize the site and maintain water quality. Any financial guarantee instrument proposed other than a performance bond shall be approved by the City Attorney.

A. Duration. The financial guarantee instrument shall be in effect for a period of at least one year (or two years in the case of a water quality facility), and shall be released when the Director determines that the site has been stabilized (or the water quality facility is operating as designed). All or a portion of the security retained by the City may be withheld for a period of up to five years beyond the one year maintenance period, if it has been determined by the Director that the site has not been sufficiently stabilized against erosion (or the water quality facility is not operating as intended).

B. Exemptions. Individual lots zoned for single family and two family residential use prior to the effective date of this Section, and individual lots subject to the standard erosion control plan stated in 5.614 shall be exempt from the security requirements of Section 5.617.

C. Conflict. Due to the immediate threat to the public health, safety and welfare posed by failure to comply with the strict provisions of the erosion control measures required under this Section, the provisions of Section 5.617 shall supersede the more general provisions of Troutdale Development Code Sections 17.050-070, where conflicts exist.

5.618 Penalties. Each violation of any provision of this Section, or any failure to carry out the conditions of any approval granted pursuant to this Section, shall be unlawful and a civil infraction subject to the enforcement provisions of Troutdale Municipal Code, Section 17.110, Abatement and Penalty.

A. Additional Penalties. In addition to those penalties available under Troutdale Municipal Code, Section 17.110, the Director may enforce the following additional penalties:

1. Issue a stop work order where erosion control measures are not being properly maintained or are not functioning properly due to faulty installation or neglect.

2. Refuse to accept any development permit application, revoke or suspend any development or building permit, or deny occupancy of the subject property until erosion control measures have been installed properly and maintained in accordance with this Section.

B. The owner of the property from which the erosion occurs, together with any person or parties who cause such erosion, shall be responsible for mitigating the impacts of the erosion and for preventing future erosion.

C. Upon request of the City Administrator or at the direction of the City Council, the City Attorney may institute appropriate action in any court to enjoin development of a site or building project which is in violation of this Section, or to require conformance with this Section.