Development, Storm Water and Erosion Source Control Strategies

Urbanization frequently results in clearing of vegetated areas. When soil erosion occurs during clearing, site preparation, and construction operations, valuable fish spawning areas can be covered with silt. Removal of vegetation, erosion and siltation can degrade habitats of birds, invertebrates, and plants.

Although only 3% of the Chehalis River Basin is urbanized, storm water is recognized as a significant and growing source of pollution in the basin. Studies from other states indicate that urban runoff from storms may be as bad or worse than the effluent from primary sewage treatment plants. Storm water runs directly into surface waters without treatment. The magnitude and frequency of flooding may increase as vegetation cover and permeable soils are replaced by impermeable surfaces. Erosion and streambed scouring results in habitat loss for fish and invertebrate species. Increased overland flows due to lack of infiltration, lower permeability, or impermeability can reduce ground water recharge, presenting serious problems when a ground water aquifer is used as a source for a public water supply, e.g. the Centralia area aquifer.

Construction practices, increased impervious surfaces, clearing and grading, filling of wetlands, and the increased use of lawn care products such as fertilizers and pesticides all contribute to nonpoint source pollution in developing areas of the basin. These issues, which are addressed in the State Environmental Protection Act (SEPA) process, become increasingly significant as the rate of development increases. Contractors must be educated in the control of erosion during construction. Developers need to learn the importance of natural drainage features and the impact of increased impervious areas. Homeowners need to be taught how to prevent hazardous household products from entering surface water and ground water.

Development, Storm Water and Erosion Goals

Significantly reduce or eliminate nonpoint source pollution resulting from development, erosion and storm water runoff in the Chehalis River Basin.

Recommend adequate plan review, inspections, enforcement of existing development regulations, and development of new regulations when needed.

Development, Storm Water and Erosion Recommendations

Issue: - Public awareness of the water quality impacts of development, storm water and erosion should be increased. The following education efforts should be conducted by city and county governments, conservation districts, and the Washington Department of Ecology:

• 1. - Work with local realtors and developers to construct model storm water facilities.
  
• 2. - Educate operators of commercial establishments such as gas stations, dry cleaners, haulers of commercial wastes, and industries on appropriate management of materials and wastes which can contaminate storm water.
  
• 3. - Develop educational programs to build support for correcting water quality impacts from storm water. Educational efforts should be geared to different audiences; for example, different materials should be prepared for high-risk businesses, such as gas stations, than are prepared for the general public.
  
• 4. - Information on the impacts of pet wastes should be included in educational programs on storm water directed at people residing in the watershed.
  
• 5. - Educate the public to spot water pollution and to notify appropriate resource agencies and landowners.
  
• 6. - Educate the public about the importance of proper home pesticide and fertilizer use, and the prevention of erosion from landscaping.
  
• 7. - Guidelines on erosion control and storm water control for single-family homes should be developed and provided to home builders and permit applicants.
  

Issue: - Cities and counties should review all existing development and land-use ordinances (e.g. subdivision, development, zoning), regulations, and enforcement methods for standards that may harm surface and ground water quality. These rules and standards should be revised to protect and improve water quality. Recognizing that the following recommendations may create potential conflicts with water conservation efforts, some examples include:

• 8. - Grassy swales or similar bio-filters should be allowed when circumstances warrant as an alternative or supplement to curbs and gutters.
  
• 9. - Semipermeable grass paving blocks and other permeable paving materials such as gravel and rock in driveways and parking areas should be encouraged rather than total coverage with impervious surfaces.
  
• 10. - The Washington Department of Ecology should work with local governments to institute reasonable and effective storm water requirements for development.
  
• 11. - Highway construction should comply with federal, state and local storm water requirements (whichever are most stringent).
  
• 12. - Review the existing enforcement methods used by county planning departments to enforce land use regulations and adopt methods other than criminal penalties (including civil citation authority).
  
• 13. - Initiate enforcement actions where voluntary measures are not taken to prevent storm water pollution from commercial establishments.
  
• 14. - Legal counsel should review existing penalties for illegal dumping of pollutants and hazardous materials and should recommend to the legislative body any changes necessary to ensure that penalties are commensurate with the potential problems. The legislative body should ensure that penalties for illegal dumping of pollutants and hazardous materials are commensurate with the potential problems.
  
• 15. - Review and modify existing land clearing ordinances, or develop new ordinances, if necessary, to ensure that no significant problems are caused by land clearing (even clearing for individual homes), while ensuring private property rights.
  
• 16. - Storm water utilities, if any, should coordinate solutions to erosion, flooding, and related problems arising from storm water drainage outside the right-of-way but associated with the right-of-way.
  

Issue: - The following steps should be taken regarding existing storm water facilities:

• 17. - The Washington Department of Ecology should change design requirements for state facility construction grant programs to require mitigation of storm water impacts.
  
• 18. - Counties and cities should continue ongoing efforts, or begin new programs, to correct water quality problems with existing storm water outfalls.
  
• 19. - Counties and cities should identify and prioritize significant storm water discharges.
  
• 20. - Counties and cities should inventory existing storm water facilities to determine if they are failing, and whether or not they lie in flood-prone areas.
  
• 21. - Possible recommendations for failing or abandoned facilities include: county/city taking over abandoned or failing systems; abandoning individual systems and providing regional facilities; and requiring a subdivision to form a homeowners' association that is responsible for maintenance.
  
• 22. - Public works departments should establish programs to ensure that privately owned storm water facilities will be maintained, including maintenance standards, responsibility for maintenance, funding, inspection, and enforcement.
  

Issue: - Wetlands, streams, and riparian areas require special protection from storm water, erosion, and development impacts.

• 23. - All jurisdictions in the basin should adopt measures which include protective ordinances and incentives that will protect wetlands and streams from filling and from major damaging alterations. Measures to provide riparian buffer strips for streams should also be adopted. Examples of such measures include incentives, purchase of significant wetlands, and ordinances.
  

Issue: - As outlined in the General Recommendations section, counties and cities should eventually prepare basin plans addressing surface water management for all significant tributaries to the Chehalis River and Grays Harbor. Plans should be prepared for priority areas with greater storm water impacts first, due to chronic water quality problems resulting from increasing population pressures.

• 24. - Basin plans addressing storm water management should include:
  
  • A. - Inventory of existing storm water facilities, and recommendations for failing or abandoned facilities.
    
  • B. - Discussion of how changes in land use will affect water quality.
    
  • C. - Education on storm water issues.
    
  • D. - Discussion and consideration of the role of roadside ditches in the water quality of storm water.
    
  • E. - Emphasis on properly engineered preventative measures rather than after-the-fact remediation.
    
  • F. - Requirement that the state Department of Transportation participate in planning and implementation of basin plans.
    
  • G. - Discussion of relative advantages/disadvantages of regional storm water facilities vs. local facilities.
    

Issue: - Cities and counties should follow standardized procedures in the design of storm water facilities, while recognizing that each facility may require specialized features.

• 25. - Consider the following in developing a design manual for storm water facilities:
  
  • A. - Support the emphasis on water quality as well as water quantity.
    
  • B. - Consider the differences in soil conditions within the watershed when developing design standards.
    
  • C. - Include a statement that the design standards are attempting to improve water quality by removal of nutrients and sediment, and control water quantity, not just control runoff.
    
  • D. - Ensure that all governmental agencies (federal, state, and local) comply with design standards.
    
  • E. - Require improvements on private property, including permanent private roads, to comply with design standards, e.g. culverts should be installed where roads cross streams.
    
  • F. - Prohibit direct discharge of storm water into waterbodies without pre-discharge treatment measures that protect water quality, including but not limited to grass-lined swales, sediment settling basins, oil and grease traps, and other measures such as the creation of wetlands for storm water pretreatment. However, the highest priority should be correction at the source.
    
  Other recommendations:
  
• 26. - The Washington Department of Health should search out and evaluate new information on how to address the water quality problems posed by pet wastes.
  
• 27. - Conservation districts, cities, and counties should become involved in storm water issues related to pesticide and fertilizer use by residential property owners, and should encourage the use of Integrated Pest Management for pesticide application and disposal by all users of pesticides.
  
• 28. - Research and implement alternatives to roadside ditch maintenance practices of removing all vegetation. An example is to design ditches to allow mowing vegetation rather than eradication.
  
• 29. - Alternatives for homeowners to get rid of unused or leftover household chemicals should be provided. This could include more publicity for a hazardous waste drop-off facility located at city/county landfills or transfer sites and more days where people can drop off unused or leftover chemicals at in-town locations at no charge.