What exactly is a watershed? No, it is not a shed or building where water is kept, but sort of, courtesy of Mother Nature. There are many definitions of what makes up a watershed, some simple and some complex. Several are included for your understanding.
A watershed is the area of land where all of the water that is under it or drains off it, goes into the same place. A watershed is the geographic boundary, usually defined by ridges, of a lake, creek, river or stream. A watershed carries water 'shed' from the land after rain falls or snow melts. Drop by drop, drip by drip, water enters the soil, groundwater, creeks, and streams making its way to large rivers and eventually the sea.
Famous late 19th Century scientific explorer John Wesley Powell's definition is: "That area of land, a bounded hydrological system, within which all living things are inextricably linked by their common watercourse and where, as humans settled, simple logic demanded they become a part of a community."
Simply stated, everything we humans do in a watershed will ultimately impact what goes on in its streams or lakes. It is not a simple issue, but very complex. All factors that go into making a stream, as well as the makeup of stream habitats, are extremely complex and interwoven. Factors that go into a stream's composition include: precipitation, topography, soils, land uses (which determine sediment and contaminant loading of groundwater and surface runoff), sunlight or shade, and streamside vegetation.
The amount of urbanization/development of a watershed has a dramatic effect on the amount of precipitation delivered, how fast to streams, and how much enters the soil or evaporates back to the atmosphere. Urban watersheds typically have fewer trees, thus less transpiration and more hard surfaces like roads, roofs, parking lots, etc., which leads to increased runoff, higher stream flow, and perhaps flooding during rain events or snow melt. Science has demonstrated that once more than 10 percent of a watershed is hardened, negative impacts will be seen in watercourses.
There are 63 major watersheds in Michigan, with 30 of those being in the U.P. The Saginaw River watershed is the largest land area-wise, containing 6,260 square miles despite the main stream being only 20 miles long. The Grand River watershed is the second largest in area and has the longest mainstream at 260 miles. The Menominee River watershed is the U.P.'s largest containing 4,070 square miles and is 116 miles long. It includes land area in Wisconsin and empties into Lake Michigan.
The Ontonagon River watershed is the largest in the U.P. that empties into Lake Superior. It is 1,362 square miles in area, over five counties: Gogebic, Houghton, Iron, Ontonagon and Vilas (Wis.). There are 200 lakes over 10 acres, one of which is the largest lake in the U.P., Gogebic at 13,048 acres, which is more than 20 square miles. The watershed has almost 1,300 miles of stream, most of which are quality trout waters.
Most of us live in the Portage watershed, in which there are several sub-watersheds, including Big, Boston, Coles, Denton, Dover, Gooseneck, Huron, McCallum, Mill, Peepsock, Quincy, Schlotz and Swedetown creeks and the Pike, Pilgrim, Sturgeon and Traprock rivers.
As there is an approved watershed management plan for the Pilgrim River, a closer look will be interesting. The Pilgrim River watershed contains 15,546 acres or 24.3 square miles in central Houghton County. Three townships, Adams, Chassell and Portage, lie partially in the watershed. There are 31.8 miles of stream, with 21.7 miles named, and the mainstream Pilgrim being 11.8 miles long. The headwaters rise in the Range Towns of Atlantic Mine, Baltic, Painesdale, South Range and Trimountain flowing east and north forming the mainstream around Superior Road, before emptying into Portage Lake. The watershed is 58 percent forested, 25 percent open, 12 percent wetlands, 4 percent developed, and 1 percent lakes or ponds. These cover types result in good water quality and an excellent trout and steelhead fishery. Although 873,526,000 pounds or 436,763 tons of copper were mined in the watershed, it remains relatively untouched from the mining, as the ore was stamped and smelted in another watershed.
Watershed management is absolutely in the best interest of any watershed and can help the communities it supports best manage its liabilities such as flooding, while enjoying the economic benefits. Watershed management can be difficult with multiple political units involved. A case in point is the Ontonagon River watershed, in which there are two states, five counties and many townships and municipalities involved. Mother Nature does not understand, nor listen to politics.