Some of the most common causes of poor drainage or standing waters are the impacts of environmental factors such as beavers and excessive vegetation. If you are observing slow drainage along a known ditch or stream, but you don’t see any signs of beaver activity or excessive vegetation, the issue could be downstream from your site. Attempt to contact neighboring property owners and alert them of your drainage concerns.

Beavers – If beaver dams are restricting flow, contact the WA Department of Fish and Wildlife’s Coastal Region 6 Office at 360-249-4628 or find your area Biologist. Dam removal requires a Hydraulic Project Approval. There may be options to reduce impacts of beaver dams by notching them, using pond levelers and installing culvert fencing. Beaver relocation may also be an option in some situations. Any activities affecting beavers or their habitats must be pre-approved by WDFW. You can visit www.beaversnw.org for more general information on beavers. 

Vegetation – Invasive and noxious weeds thrive in and along drainage channels. Problem species such as reed canarygrass (pictured) can outcompete native plants, create dense stands and lead to siltation in streams and ditches. Removing vegetation below the ordinary high-water line (OHWL) in fish-bearing streams requires an HPA from WDFW and must occur in the assigned fish-window for that stream. Drainage ditches and fish-bearing streams have different regulations for removing vegetation, and permits may be required in some instances. Contact Pierce County staff or your local WDFW office for additional information. 

Changes in land use or management can lead to drainage problems. If farm practices have been altered in recent years, soil conditions may have changed. This may include a change from pasture to cropland (or vice versa), introducing a new tillage practice, changing equipment or tractors, or intensifying livestock grazing. There are resources available to farms and landowners to help identify and alleviate these problems, including from WSU-Extension, Pierce Conservation District and local USDA-NRCS staff.

Practices and conditions that can negatively affect drainage:

• Repetitive tillage using the same implement
• Working in fields when soil moisture is high
• Over-inflated tires on tractors and implements
• Not using designated field roads/paths or feeding sites for livestock
• Low organic matter content
• Lack of crop rotations
• Poorly maintained drainage features and infrastructure

Soil management to reduce compaction:

• Subsoiling in early fall and in spring, if possible
• Vary tillage equipment usage by depth and action
• Inflate tires to lowest possible rating for safe use
• Cover crops or 'green' manure
• Crop rotations, including fallow cycles
• Repeated use of areas already compacted by equipment or animals
• Avoid over-irrigating fields

Over time, on-farm drainage infrastructure (ditches, culverts, ponds) and natural streams that convey run-off can be damaged or altered. To determine if this is the cause of your drainage issue:

• Inspect ditches for proper shape and gradient to convey runoff
• Inspect culverts for damage or sedimentation
• Monitor vegetation growth within and along channels

Any work that needs to be performed in these ditches or streams may require a Hydraulic Project Approval from WDFW and/or permission from the Army Corps of Engineers. Pierce County also regulates activities in some ditches and all streams, so please contact the PPW Agriculture Program for assistance before performing any work.

Some parcels rely on County infrastructure in the form of roadside ditches to provide adequate drainage. Roadside ditches are regularly serviced by mowing and clean-out crews. Different levels of service are provided depending on need and available resources. These roadside ditches can also be blocked by sediment and vegetative material, but landowners should not perform any maintenance on them. 

If you see sediment or debris in roadside ditches, please complete the Request for Action form, providing as much detail as possible.

Soil conditions are impacted by regular farming activities and other land uses. Soils also have inherent natural qualities that impact their suitability for agriculture and their likelihood to experience drainage or flooding problems. The soils present on any given parcel are mapped by the USDA-NRCS (Pierce County Soil Survey). Soil maps should be used   to better understand your site and how its soil properties might influence drainage. Soil maps are not 100% accurate and cannot account for every small inclusion of soils that do not behave as the primary mapped soil in an area. Soil qualities change as you go deeper in the profile, and sometimes there are subsoil layers that can reduce infiltration and limit root growth.

Consulting a soil scientist or resource conservationist through USDA-NRCS can help identify if there are natural drainage problems in your soils and how to potentially work around them. There are steps that can be taken to alleviate naturally occurring drainage problems in some soils. However, most poorly drained soils are not capable of being sufficiently amended to improve large areas of poorly drained ground. Soil type and drainage capabilities are important aspects of site selection when establishing a new agricultural land use, so it is best to conduct a thorough review of a site's soil properties before finalizing your plans.