In an effort to minimize the destructive potential of stormwater runoff and spring thawing, many roads have a series of ditches and culverts surrounding them. The water that flows through these structures carry silt, foliage, and other debris along with it. The accumulation of this debris in ditches, flash flooding and other natural disasters can cause erosion underneath the road base, or flooding out onto the roadway surface depending on the topography of the area making the road nearly impassable.
When culverts become plugged, water will tend to pool out onto the roadway, and possible wash out the road or driveway approach. Spokane County will clean out the culverts and re-establish the ditches on county right-of-ways as necessary. Since there are limited resources available this work is done on a worst-first basis. Even though the ditches are somewhat cluttered, the work may not be done immediately.