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The largest tributary to Lake Mendota, the upper Yahara River begins in Columbia County and passes through Cherokee Marsh (the watershed's largest wetland), where it doubles in size at its confluence with Token Creek. Above Token Creek, the Yahara River drains 32% of the Lake Mendota watershed, supplying about 22% of the total surface water runoff to the lake. The tour route follows the Yahara River north to its headwaters, goes briefly out of the Lake Mendota watershed into the Crawfish River Watershed and then through two closed sub-watersheds before returning south. The internally drained areas of Goose Pond and Schoenberg Marsh usually have no surface water outlet. Directions to Governor's Island: Take Troy Dr. west from Northport Dr. (Hwy 113). At Mendota Mental Health Center sign, bear left. Turn left onto Cinder Lane and follow to gravel parking area. You will notice a variety of land uses on this tour. Many are harming water quality, but some are definitely helping to improve it.

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Click on the image for a PDF version of the map.

Distance: 49.6 miles. Difficulty: Long but few hills.

1. The Mendota State Hospital grounds contain portions of two impressive Native American mound groups, including some of the finest and largest effigy mounds found anywhere. Large birds (one with a 624-ft. wingspan), panthers, a deer, bears, many conical and several linear mounds are found here, representing two distinct periods of mound building spanning over a thousand years (100 to 1200 AD). To view the mounds, check in at the Administration Building, where maps are available. Archaeologists have also found village sites and corn hills here.

2. Westport Rd. Between Greene and Lighthouse Bay Dr. Surface water passing through these wetlands on its way to the lake is cleansed of sediments and excess nutrients. In 1993, high water levels floated a 12 acre vegetation mat from this wetland away to the other side of the lake. Most of the wetland areas bordering Lake Mendota and the lower Yahara River sit atop the lake bed of "glacial Lake Yahara", which covered a larger area than present-day Mendota. It formed when the glacier dammed up the Yahara River during the last Ice age. Fine, clay-rich sediments drain poorly, leading to wet soil conditions favorable to wetland plants and formation of peat (spongy, partly decayed plant material that builds up in wetlands, giving them their water-holding properties).

3. The upper Yahara River is Lake Mendota's largest tributary extending into southern Columbia County, although during dry periods, more water comes from Token Creek, another major tributary, which flows into the Yahara about five miles upstream.

4. Cherokee Lake. Dane County Parks' purchase of the upland bordering the Yahara River protects water quality and provides upland buffer areas important for wildlife habitat. The marsh is accessible by foot trail at Yahara Heights County Park, reached by turning right on Riverview Dr. and entering the park at the gate near the corner with Caton Lane. Siltation from the upper Yahara River basin necessitated a 1994 million-dollar dredging project to keep the river's outlet into Lake Mendota navigable and to maintain a channel into Cherokee Lake. The dredge spoils can be seen here (1/4 mi E of Hwy 113 on to S of River Rd). After drying out, the spoils will be sold as topsoil. Spring-fed wetlands west of Hwy 113 (near River Rd) are being filled in as this area undergoes development.

5. Cherokee Marsh can be seen at a distance off to the right, across the Yahara River. Cherokee Marsh is the largest and arguably the most important wetland area in the Lake Mendota watershed. Situated at the headwaters of the Yahara chain-of-lakes, this high-quality wetland is a critical component of the Lake Mendota watershed. A wide variety of habitats, including rare calcareous fens (fed by upwelling groundwater) can be found here.

6. DeForest/Windsor water tower. In this area of rapid development, erosion control at construction sites has become increasingly important for water quality protection. Currently, about 1/4 of the sediment and

1/5 of the phosphorus contributions to lake Mendota come form construction sites-even though these sites make up only about 0.2% of the watershed. Good site planning and enforcement of erosion control ordinances can greatly reduce this. As the population in the watershed increases, demand for water does as well. Virtually all domestic water in the watershed comes from wells. Municipal wells such as those serving DeForest tap a large, high-quality aquifer in sandstone bedrock, and usually extend 300 to 700 feet below the land surface. Increasing water demand has led to a regional drawdown of the water
table, particularly around Madison, affecting some springs and altering the movement of groundwater.

7. Five ponds are found to the N of Hwy V between Morrisonville and Grinde Rds. Part of the Yahara's headwaters, these five intermittent, groundwater-fed ponds are excellent birdwatching areas and are an important resource for migrating birds passing through in the spring and fall.

8. Arlington Research Farm (Headquarters is off of tour route, 0.5 mi. farther north on Hopkins Rd.). One of 13 experimental farms operated by the University of Wisconsin, Arlington Research Station is used for a wide variety of agricultural research projects, suh as evaluating practices to reduce soil erosion and the need for fertilizer and pesticide application.

9. This is the Crawfish/Yahara River divide. Waters separated here will meet again at the Yahara/Rock River confluence in southern Wisconsin.

10. Harvey Rd wetlands [just off tour route, on Harvey Rd. between Cty. DM and Manthe Rd] are especially good to visit in spring, when fields are flooded. A wide variety of shorebirds, ducks, geese, swans and often rarities such as Ross' Geese, can be seen close to the road.

11. Cross back into Lake Mendota Watershed and pass Schoenberg Marsh. Grassy fields adjacent to this extensive wetland provide ideal habitat for nesting waterfowl and grassland birds. In spring, waterfowl, including Canada and Snow Geese, Tundra Swans and Canvasbacks are present. In summer, Yellow-headed Blackbirds, Ruddy Ducks and Black Terns nest in the area. Schoenberg Marsh is the low point in an isolated subwatershed that is not connected by surface water to the Yahara/Mendota system. However, water that soaks into the ground, recharging groundwater in this area does move toward Lake Mendota.

12. Goose Pond Sanctuary. [On both sides of Goose Pond Rd 1/2 mi. N of Cty K] Wetland and prairie restoration is ongoing at this 173 acre site that is owned and operated by Madison Audubon Society. Goose Pond is a prairie pothole that is noted in spring for its variety of waterfowl, including Tundra Swans, in summer for grassland and marsh birds such as dickcissels, bobolinks and ruddy ducks, in fall for large numbers of ducks, Canada and Snow Geese and in winter for open country birds. Wetlands surrounding Goose Pond protect surface water quality from sediments and nutrients washing off agricultural land. Like the Schoenberg Marsh subwatershed, the Goose Pond subwatershed has no surface water outlet except in very wet years, so all water drains to Goose Pond, and much of it soaks into the ground. As groundwater, it moves toward Lake Mendota.

13. NE of corner at Patton and Hahn Rds. As the number of livestock kept on each farm increases, so does the difficulty of disposing of manure without contaminating surface water. Storing manure until it can be spread is a common solution, but at some sites, expensive structures must be built. Nutrients from properly applied manure are incorporated into soil and ultimately taken up by crops. Manure at this site is spread by means of irrigation.

14. 100-Acre wetland [Patton and Schumacher Rds]. There is good birdwatching here but no public access beyond the road. Because wetlands high in the watershed protect water quality down stream, the Priority Watershed project seeks to restore small wetlands lost long ago to draining and filling.

15. Schmidt's Woods [west of Patton Rd.] include 33 acres of mature oak hickory forest and 12 acres of restored prairie. Near the entrance, the road cuts through a kame, exposing sand and ice-rounded boulders deposited there by glacial meltwater. Contour plowing and strip cropping are erosion control techniques that are visible on surrounding farmland.

16. Recently opened limestone quarry [N of Easy St. at intersection with Cty I]. Dolomite (a magnesium-enriched limestone) quarried here supply farmers (who need lime to control soil pH) and roadbuilders. Good quarry planning and oversight will protect groundwater exposed to contamination as protective soil is removed. Landscaping efforts will keep the site from becoming an eyesore. Dolomite and sandstone bedrock underlying the watershed were laid down in an ancient sea. Below these formations, beginning at about 900 feet below the surface is pre-Cambrian granite and other crystalline bedrock, part of the same formation known as the Canadian shield, which surfaces in northern Wisconsin and Minnesota.

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