The Huron River watershed drains approximately 900 square miles before empyting into Lake Erie and lies within portions of seven Southeast Michigan Counties: Ingham, Jackson, Livingston, Monroe, Oakland, Washtenaw, and Wayne. Malletts Creekshed is a subwatershed of the larger Huron River watershed in Washtenaw County. The Creek is under the jurisdiction and stewardship of the Washtenaw County Drain Commissioner.
Malletts Creek is the largest and most degraded stream within the City of Ann Arbor. It originates at the Ann Arbor Airport in Pittsfield Townshipand then flows, both above and below the ground, through residential, commercial and industrial areas as well as along major roads. All in all, the creekshed encompasses 5 local political districts including the City of Ann Arbor, Ann Arbor Township, Scio Township, Lodi Township and Pittsfield Township. The main tributary is approximately 4.7 miles long and its relatively small creekshed, or area of land that drains into the creek, covers approximately 11 square miles or about 40% of the City of Ann Arbor. The Creek ultimately discharges into South Pond which is adjacent to the Huron River after it has served roughly 25,000 people.
During the last 30 years, there has been a substantial amount of development within the creekshed. Although much of the creek is piped underground to make room for development, some of the creek is still "daylighted" and can be seen from houses, offices, Briarwood Mall, and other venues. Major land use conversions during that time have been to industrial use (557 total acres) and commercial use (258 acres), but Malletts creekshed also experienced a residential housing boom with 414 acres of new residential development since the 1960's. Over half of this new residential development has consisted of dense multiple-family housing which, in terms of impervious surface increases, has had a large detrimental impact on creek quality.
Malletts Creek is an urban stream and as such, has suffered the impacts of heavy stormwater runoff, high pollutant loads, and thus, has experienced a progressive degredation in quality. Sedimentation is a problem in Malletts Creek. While vegetation along some of its banks has helped to stabilize them, erosion is evident along many stretches of the creek and is apparent in the murky waters filled with silt. In some places, the erosion rates have been calculated at roughly 112 tons per year. Much of this sediment, and the pollutants it carries, has ended up in South Pond as it acts as a "catch basin" for the creek before it joins with the Huron River. Temperature pollution is also a problem in the creek, resuting in the loss of a diverse system of aquatic biota that are sensitive to warmer water and cannot adapt to this stressor. This excessive warming is due to the nature of the sources of Malletts Creek's hydrology. Most of the hydrologic inputs are derived from surface runoff. As this runoff, or stormwater, washes over a warm, highly impervious landscape instead of infiltrating through the soils to be cooled and released as groundwater, stream temperture increases and creates an unhospitible habitat. High loads of nutrients, like Phosphorous and Nitrogen, are also culprits of stream degredation. These pollutants cause excessive algal growth that competes for light in the aquatic system, again, depleting valuable biota in the stream. Nonpoint sources of these nutrients, or sources other than those found at the end of a pipe, have been cited as major contributors to nuisance algal growth in Malletts Creek. These nonpoint sources largely consist of detergents from residential car washing and lawn care inputs that often flow directly off driveways and into the stormsewer system, and flow directly into the creek.
Macroinvertebrate studies, or studies of the diversity and abundance of pollution sensitive aquatic bugs, in the creek, have shown that the stream is poor habitat for many creatures. These studies are used as indications of stream heath and the potential for stream restoration. These studies on the creek have recently shown that Malletts creek is further degraded that other urban streams in the area. For instance, it is known that population diversity increase with the size of the watershed. Thus, Malletts, which is larger than Traver Creekshed (only 7 sqare miles), should have more diversity than Traver. However, studies actually show only 18 taxa and 3 pollution indicator species were found in Malletts, whereas Traver had 29 species and 9 pollution indicator species. Click here to see the water quality status of certain Malletts Creek monitoring sites as compared to other creeks in the Huron River Watershed from 1993 to 1998.
Although Malletts Creek has suffered severely from the above listed problems, community officials and creekshed stakeholders have begun to address them systematically. The creek is currently under restoration planning through a cooperative effort from the Washtenaw County Drain Commissioner, the City of Ann Arbor and Pittsfield Township. With help from citizens who formed the Malletts Creek Association, restoration possibilities include both structural and non structural efforts to restore this urban stream to its best possible condition.