Role of soils in the design and implementation of Wilson Creek and Frenchman Hills projects

Wilson Creek & Moses Lake, Grant County


Results of soils investigations were integral to the design of Wilson Creek and Frenchman Hills Wetland Reserve Program (WRP) projects.

Soils investigations at the Wilson Creek site documented there were deep, peaty soils (Saltese series) throughout the area. The preliminary design for this project included contour dikes. Organic, peaty soils are generally unsuitable for dike construction. This was discussed with the Natural Resources Conservation Service (NRCS) project representative and Ducks Unlimited (DU) engineer, and the design was changed to include only excavations into natural hydrology, rather than dikes. The Frenchman Hills site is owned by the Washington State Department of Fish and Wildlife (WDFW). It is an area of sand dunes adjacent to a large irrigation water wasteway. Lower lying areas in close proximity of the wasteway are wet soils (Wanser series), and higher dunes are dry soils (Quincy series). WDFW had enhanced the hydrology of the area in the past by routing water from the wasteway through a series of dikes and structures which would pond water during periods when waterfowl nesting and rearing occur. The site dried out in the early 1990s, due to inlet channels becoming plugged with vegetation, and water control structures that were inadequate or had failed. A wetland determination prior to WRP design and construction documented the extent of past wetland hydrology. There were extensive areas where soils exhibited hydric soil indicators (redoxomorphic features), that were now relict, and where most wetland plants were either dead or dying. Plans are to use WRP to restore these areas so they will encompass at least 50 percent of the restoration area. Soils investigations aided the design and construction by evaluating the suitability of soils for channels and footings for planned structures. Areas of included soils with shallow, thick petrocalic horizons (caliche) had to be either avoided or depths of channels lessened. Also, it is curious why water would pond in these very sandy soils in the first place. Hence, soils investigations occurred to try to document why.


Ivan Lines and Brian Heck of Ducks Unlimited - Project design and implementation Greg Fitzgerald, Mikel Moore, and Jim Tabor with WDFW - Design review, implementation, and funding Bonneville Power Administration (BPA) - Seven landowners of the Wilson Creek project area - Planning, contract management, design review, implementation, and soils investigations Ernie Holt, Paul Majer and Ken Drecksel with NRCS.


The Wilson Creek WRP project is in low lying fields along Crab Creek that historically would pond for extended periods during spring runoff. Following channelization of the creek, fields were still difficult to farm in wet years, and in dry years crops did not grow well, unless irrigated. This was marginal farmland. A group of landowners interested in wildlife and wetlands applied for permanent WRP easements in these fields. DU and NRCS engineers at first planned to dike fields to create ponding. After soils investigations, it was necessary to excavate into hydrology to accomplish this because the deep organic soils were not suitable for diking.

The Frenchman Hills WRP project will restore hydrology to artifical wetland areas along Frenchman Hills Wasteway on WDFW property. This will create habitat for waterfowl. Soils investigations determined the extent of areas which had previously been wetlands which planners and engineers seek to restore. Soils investigations also evaluated the suitability of locations for planned structures and channels, and researched why a water table exists in the sandy soils at this location.


WDFW, NRCS (WRP), and BPA funded these projects to restore wetland hydrology and create wildlife habitat mainly for waterfowl. DU and NRCS engineers designed the projects. DU and NRCS will implement the projects. Soils considerations were integral to accomplish this restoration/enhancement.


Two WRP projects will be accomplished to restore wetlands and enhance wildlife habitat.


Ken Drecksel, Central Area Office, (509) 754-3023

NRCS, Spring 2007

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