Friday, March 13, 2015

Park City Water Sidebars


Water use in the Park City area was historically focused on surface water which was used for agriculture and mining processing.  Ground water was a nuisance to mining and was pumped and drained to the surface for disposal.  Water from the mines was used in town for many years until we discovered that its quality was questionable for human consumption.   Water supply now includes importation of treated surface water from the Weber River to augment the harvest of clean groundwater from deep wells and springs. 

Our population in the Snyderville Basin is expected to double again in the next 20 years bringing with it challenges and choices between conservation and consumption, balance and blind ignorance, sustainability and selfishness.  Water demands are expected to out strip supply by 50 to 100 percent over those periods.  Importing new water into the basin is necessary and critical as we outgrow the supply that we have.  Fortunately water flows towards money but eventually we will have to balance our supply with our demand. 

Climate and Water

Park City is an alpine - high desert climate, situated at the northern tip of the Colorado Plateau at just the right latitude and elevation to enjoy alpine winters and sunny dry summers.  Drift 100 miles north and you are in the cold, cloudy continental climate of the Tetons and Snake River.  Drift 100 miles south and you are in the sweltering Great American Desert and the Canyon country.   Here in the rain shadow of the Wasatch Mountain we enjoy the Great Salt Lake effect and the Greatest Snow on Earth and the climate is just right. 

John Wesley Powell, Grand Canyon Explorer and founder of the U.S. Geological Survey, recommended to Congress in 1878 that western drainage basins should live on solely the precipitation that falls in their individual geographic basin, encouraging wise use and conservation.  Of course Congress categorically dismissed Powell’s sustainability sentiments and set about re-plumbing the rivers and waters of the west.    Park City continues that tradition by importing new water to the basin from the Weber and Provo Rivers.

Water Geology

The Snyderville Basin geology is bounded by folded and faulted sedimentary rocks, mostly sandstone, quartzite, shale and limestone to the west and south, and by the Keetley volcanics, tuff and breccia to the east.  The basin is filled with unconsolidated alluvial (stream) and colluvial (glacial) deposits, as thick as 275 feet deep.  These deposits are typically course grained at the mountain interface, which is great for recharge, but are unfortunately fine grained in the basin and therefore do not yield water as easily as many of the unconsolidated fill basins in Utah. 

Municipal wells in the Park City area therefore withdraw water from the underlying consolidated rocks, such as the fractured and faulted limestone and sandstone.  These rock formations are locally broken into separate block formations that can inhibit or isolate water flow and withdrawal, which can make finding reliable ground water difficult.  This water, which recharges in the bedrock outcrops high in the mountains, typically takes 15 to 40 years to move through the system, although much older water is still being mined from our underlying bedrock and aquifers. 

No comments:

Post a Comment