One inch of rain falling on our 16,000-acre watershed generates 434 million gallons of stormwater. All that water has to go somewhere! CDID #1 makes sure the water gets where it needs to go in order to keep the properties behind our levees dry.
Sloughs, Ditches & Drains
We maintain roughly 35 miles of internal sloughs, ditches and drains - some natural, some improved and some entirely man made. These drainage ways serve two purposes - they collect and convey stormwater to our pumping stations, and they provide storage for heavy rainfall events which can exceed our pumping capacity.
CDID #1 operates seven pump stations which represent a combined pumping capacity of roughly 700,000 gallons per minute. These pump stations are located throughout Longview and are critical for removing stormwater and preventing flooding. All of the water pumped out of the system eventually goes to the Columbia River.
Several of our drainages are built on easements, which means anyone wanting to do work within the drainage right-of-way or discharge to the ditch must apply for a permit.
Discharges from our ditches to surface waters are permitted as a Municipal Separate Storm Sewer System (MS4) under the Western Washington Phase II Municipal Stormwater National Pollutant Discharge Elimination System (NPDES) permit. CDID#1 is considered a Secondary Permittee to the City of Longview. As such, we are required to adopt and implement our own Stormwater Management Program to:
- Control stormwater flows
- Educate the public
- Eliminate illicit discharges
- Reduce contaminated runoff
- CDID#1 Stormwater Management Program (PDF)
- CDID#1 Annual Stormwater Report for 2019 (PDF)
- City of Longview Stormwater Manual
- Cowlitz County Stormwater Manual
- Stormwater Management Manual for Western Washington