CSGP: Assess Your Site
There is quite a lot of research that should be conducted prior to completing the Notice of Intent (NOI) and the Stormwater Pollution Prevention Plan (SWPPP) for your site. It may be helpful to look at our Example NOI and Ecology’s SWPPP template as you assess your site to get an idea of what information you may need. This information includes, but is not limited to, the items below:
Gathering information regarding the history of your site can be a crucial step in gaining permit coverage without delay. You will want to gather any information about your site that you can find. This can be existing site maps or drawings, information regarding any previous activities that occurred on the site, or existing geotechnical or environmental reports.
You will need to collect the contact information of the site owners and operators. It is important that the site owner is aware of the permit requirements, and has given proper authority to the operator via contract and/or signatory authority. It is also important to identify who the operator is, and if that will change throughout the life of the project, requiring a Transfer of Coverage.
It is crucial to understand the soil type that you will be working in. The composition of soil plays a critical role in determining the most effective ways of preventing erosion and sediment control issues and staying in compliance with your stormwater permit.
There are several ways to evaluate the soils on your site, but one of the most universal ways is to access the USDA Web Soil Survey. If you put in your address or get close to the area and draw an AOI (area of interest) box where land clearing will occur, you will be provided a narrative description of the surrounding soil types. These surveys may also be accessed via a plug-in to Google Earth.
It is important to consider how the climate your facility is in will affect your site. Different areas of Washington can experience significantly different weather patterns. Western Washington, for example, is known for its long periods of light rain during the winter, while areas of Eastern Washington are often drier but may experience heavier downpours or significant snowfall. The rainfall intensity (how hard it is raining), duration (how long it is raining), and seasonality (what time of year it rains) can play an important role in how stormwater is managed on your site, and how to most efficiently finish your project.
Predictive Weather Resources
Receiving Waters & Sensitive Species
It is important to know where the stormwater goes after it leaves your site. Some sites may simply run off into a field and infiltrate into the ground, while others may enter a complex system of ditches and drainages before entering a sensitive water body. It may be useful to use local GIS mapping to see where any of these conveyances lead. The receiving waters your stormwater enters can play a critical role in sampling, monitoring, and treatment requirements, so it is important that the receiving waters are correctly identified.
Local jurisdictions may have requirements that will influence BMP selection, drainage design, and operational influences (noise restrictions, traffic flow, etc). These jurisdictions may also have lower disturbance thresholds that require additional permitting. It is important to review local codes and regulations before starting a project.