Programs > Farm Management Services >Agricultural Drainage Program > Snoqualmie Valley Agricultural Drainage Survey

King Conservation District
Agricultural Drainage Program

The King Conservation District is facilitating increased participation in the King County Agricultural Drainage Assistance Program through landowner outreach, financial assistance and project monitoring. Surveying landowners to assess drainage problems across King County is an essential first step in the project. Information gleaned from the survey will be used to design and implement programs for landowners interested in improving their field drainage.

KCD is collaborating with King County Stormwater Services on an agricultural drainage survey of landowners across all of the county’s Agricultural Production Districts. As a starting point, in early 2015 we partnered with the Snoqualmie Valley Preservation Alliance on an assessment of drainage problems the Snoqualmie Valley and below is a summary of our preliminary findings.


Agricultural Drainage ChartIn mid-February, 2015, we mailed survey forms to approximately 300 landowners in the Snoqualmie Valley. Seventy-five landowners responded to the survey, representing 2,964 acres with an estimated 17.4 linear miles of drainage. 70% of the respondents said their operations are impacted by poor drainage. The landowners also indicated that drainage problems have been building on their fields for an average of 30 years.

Landowners reported flooding from the Snoqualmie River is the primary cause of drainage problems in the valley. Major impediments to getting the water off fields following flood events are sediment and vegetation in drainage ditches, and blockage of drainage channels by beaver dams. The survey also showed many landowners are impacted by poor drainage on neighboring properties.

agricultural drainiage mapAfter river flooding, beaver dams were identified as the third highest cause of drainage problems in the Snoqualmie Valley. In the initial survey, 30 landowners reported an estimated 2,200 acres impacted by poor drainage caused by beaver dams.

agricultural drainage chartDairy and livestock have long been the primary farming operations in the Snoqualmie Valley, so pasture and hay fields are most impacted by poor drainage. Surprisingly, farm access roads were identified as the next highest concern, followed by vegetables, nursery crops, berries, and Christmas trees.

Agricultural Drainage Chart. What causes problemsLandowners seeking to resolve drainage problems are confronted by several major barriers, starting with project costs, permitting, regulations, and the need for technical assistance. Over the next several months the agricultural drainage survey will be expanded to all of the APDs and the findings will be used to develop additional programs and services to assist with keeping land in production across King County.