Immediate Future | Mitigation for the South Lawrence Trafficway Begins
Beginning in September 2008, Baker University, under the leadership of Dr. Roger L. Boyd, started the conversion of 140 acres of cropland back to wetlands. The project was approved by an agreement with Kansas Department of Transportation and financed by funds from the Federal Transportation bill of 2006.
Phase I of the Mitigation: Restore 140 Acres of Wetlands
These crop fields are within the 100-year floodplain, and a significant portion of Tract B is part of the floodway. These acres had been wetlands before conversion to crop fields in the 1800s, just like the Old Haskell Farm, which is now referred to as the Baker Wetlands. As such, the soils were hydric (they are heavy, dense clays that hold water), hydric vegetation was present, and the area held water for a portion of the year. Those soils are still hydric and hydric plants still occur. Our surveys in the fall of 2008 located 14 species of hydric plants along the drainage ditches in both tracts.
People might think we are creating wetlands on this acreage, but in fact, we are restoring wetlands that used to be here. The significance is that a vast majority of the wetland mitigation projects in this country fail because mitigation projects attempt to create new wetlands where they had not previously occurred and because monitoring is inadequate. A study by the National Academy of Science found that more than 70 percent of created wetlands fail. Restoration projects, however, succeed more than 80 percent of the time.
The process of restoring these wetlands began as soon as the crops were harvested (see illustration below). The corn stalks were mowed so they would not interfere with the earth movers. We established a permanent hectare grid across both tracts. We also began collecting seeds in the original Baker Wetlands and elsewhere around the county. Seeds from 42 species were collected, with a total weight of 12,000 grams. Examples of these seeds.
Next, the location and shape of the swales were marked in the field using a tractor and three-bottom plow. The swales were then excavated using earth movers. The swales were excavated to either 6 inches, 12 inches or 18 inches deep and from 16 feet to 64 feet wide. The length of each swale varies from 60 feet to nearly 1,200 feet, and the pattern is random, all depending on the initial site plan (see illustration below). Fifty-seven swales were excavated, requiring the removal of more 56,000 cubic yards of soil. Some of this soil was used to construct the berms that parallel Louisiana Street and N. 1250 Road. Wetlands restoration photos.
The purpose of these swales is to disrupt the linear pattern created by agriculture over the past century, to create a pattern similar to the meanders, swales, and oxbows that might typically be found in an active, untouched floodplain and to create a variety of habitats for plants and wildlife. Some swales will retain water much longer than others. This will stimulate the presence of different species of hydric plants and thus the presence of different invertebrates and aquatic vertebrates. Several swales will go dry periodically, and this will eliminate the presence of fish, which can be fierce predators on tadpoles and other aquatic invertebrates.
The seeds were dispersed around the perimeters of the swales in mid-April 2009 and many germinated fairly soon afterward. Some species, however, may take several years to germinate. The area will be monitored, and weeds will be controlled as needed. Keep in mind that what one person refers to as a weed may be excellent wildlife food and be of great ecological value. All that remains is help from Mother Nature and Father Time.
Another component of the plan is regulation of water levels. This will be accomplished through two water-control structures (WCS). The location of these structures is illustrated above by the tan arrows. The WCS in Tract A is a small plastic unit. If necessary, it can be relocated during road construction. The WCS in Unit B is a large, three-bay concrete structure. In both structures, boards will be sealed into the bay, which backs up the water into the tract. Once it gets to the top of the board, it flows over and through the outlet. The height of the boards determines the depth of the water and the extent of the flooding inside the tract. Another reason for the difference in size between the two WCS is the drainage area of each tracts. Unit A drains only about 80 acres, so it can be relatively small. Tract B, however, drains about 650 acres beginning on the west side of US Highway 59. This larger drainage area will deliver more water into the tract, so a larger outlet must be in place. The process of building this larger WCS is illustrated in the Water Control Structure photo album.
A lake is located in Tract B. It is slightly less than 5 acres in surface area, but its sides are steep and it is 15 feet deep. This angular pond was a “borrow pit” for fill dirt to construct the ramps on the east side of the South Lawrence Trafficway bridge over US Highway 59. Several improvements have been made to increase the wildlife value of this lake. The elevation of the lake was lowered and irregular-shaped channels were excavated around the lake to give it a more natural appearance. About a dozen cedar trees of various sizes were submerged in the lake to create fish habitat, and two floating rafts were anchored in the middle of the lake to create additional habitat. Once the WCS is closed and water is backed up in the channel, it will flood these channels around the pool, creating a shallow-water habitat around the edge. This will be beneficial to several organisms that depend on this type of habitat. Another advantage of the lake is that all runoff from the west enters the lake, allowing the silt load it carries to settle out rather than moving on down the channels and causing other problems there. In addition, the lake will serve as a discharge location from the surrounding water table, and this will provide a more continuous flow of water through the outlet channels and pools during dry weather.
Down the hill from the silo is a smaller pond that serves as a settling basin. It is slightly deeper than the outlet channel and allows silt that flows into the pond to settle out so that it does not flow down to the outlet structure. Maximum depth, when full, is about three feet.
In addition to monitoring vegetation, we will monitor the changes in the surrounding water table as the previous agricultural fields are rehydrated. Two monitoring wells were established in Tract A and four in Tract B for this purpose. Both are constructed of a single 10-foot-long PVC pipe, 2 inches in diameter. On the end is a foot-long screen that allows water to seep into the pipe. The well hole is sealed around the outside of the pipe to prevent surface water from entering the well. The water table is measured with an electronic tape. Measurements are added to a database that calculates the elevation of the water table, both in regards to the surface and in relation to sea level. The maximum depth of the wells is between 8 and 9 feet below the surface. In the spring of 2011 the water table was within a few inches of the ground surface to a depth of 3 feet from the surface, depending on the well. During the severe drought of summer and fall 2011, however, the water table was between 7 and 9 feet from the surface. Still not too bad for an old farm field.
An additional feature of this first phase of the mitigation project is the construction of a small visitor parking area adjacent to the farmhouse. A small information kiosk is located next to the parking lot and contains a map that explains ways that visitors can experience the transition from crop fields to wetlands. Once the visitor center is built, we will convert the existing silo into an observation tower. We have also constructed a picnic pavilion on top of the footings for the old milk barn next to the silo, which will contain information panels with much of the same information found on this Web site. Construction of an 1,800-foot walking trail has been completed, and construction of a 1,000-foot-long boardwalk down to the pond and back was completed in May 2010.
Phase II: Completion of the South Lawrence Trafficway & the Adjacent Mitigation Project
Once funding becomes available in the fall of 2013 to complete the 5 miles of the South Lawrence Trafficway from US Highway 59 east to K-10 Highway near Noria Road, the remaining components of the mitigation project will be completed. Between 140 and 150 acres of floodplain farm ground to the east of County Road 1055 (E 1500 Road and the extension of Haskell Avenue) and on either side of N. 1250 Road, will be restored to wetlands. Where this restoration will take place is indicated on the map below. A 17-acre portion of this area was restored to wetlands beginning in the early 1990s and is often referred to as the Santa Fe mitigation site.
Once the trafficway is completed, Louisiana Street will be removed and relocated to the west half a mile, a portion of N. 1250 Road from the farmhouse down the hill to Louisiana Street will also be removed. The berms can then be relocated to the east, next to the Wakarusa Watershed District Flood Canal. This could expand Tracts A and B by approximately 6 to 8 acres. The hill to the west of Tract A will also be excavated for fill during construction. The portions that are low enough can be restored to wetlands by depositing a layer of hydric soil on top of the area. This hydric soil is being stockpiled to the east of the existing farmhouse. This could gain an additional 10 to 12 acres of wetlands. On the east side of the existing Wetlands, the removal of Haskell Avenue may gain another 4 or 5 acres of wetland habitat. The relocation of these two roads will increase the acreage of wetlands in the area, but more important, it will make the area a more contiguous habitat and establish a buffer to the east and west of the original Wetland property. In addition, there will be a 12-foot noise wall and hike and bike trail on the south side of the SLT within the original property. This will greatly improve the overall value as a wildlife refuge.
Locations & Details of Phase II
The red dashed lines indicate the relocation of Louisiana Street to the west and Haskell Avenue to the east.
Overall, the estimates are that we will lose 56 acres of the original 613 acres south of 31st Street and gain 304 acres of restored wetlands. In addition, there will be about 50 acres of restored upland prairie and 25 acres of restored riparian habitat added to the area. This will total about 937 acres of habitat that will be managed for wetlands and wildlife in floodplains south of the completed South Lawrence Trafficway.
As indicated in Long-Range Plans, other benefits to the Baker Wetlands and the people of Douglas County from completing the SLT along the 32nd Street alignment include improved traffic flow, $37 billion in economic benefits, construction of a visitor center, improved access to the Wetlands at four locations, funding to staff and manage the area in perpetuity, and an agreement with Douglas County to ensure that the Wetlands will remain forever. In addition, the City of Baldwin City and RWD #4 will be able to locate their water lines in the shoulder of the relocated Haskell Avenue, allowing them to abandon their water lines that currently exist inside of the Baker Wetlands, thereby improving the maintenance of the lines.
All of these components are accumulative to ensure an improved wildlife habitat and visitor access as well as increased appreciation for wetland habitats by the general public.