9342 - Laserfiche WebLink

Home Browse Search

Table 2. Summary of procedure used to aggregate nutrient data in the Gore Creek watershed into selected nutrient constituents (from Mueller and others, 1995) [mgIL, milligrams per liter; N, nitrogen; N03, nitrate; P, phosphorus; P04, orthophosphate; *, parameter determined by using the procedure listed for nitrite, as N; **, parameter determined by using the procedure listed for nitrate, as N] Constituent Nutrient data parameter name Nutrient data parameter code 1 Ammonia, as N Nitrogen, ammonia, dissolved (mg/L as N) 00608 Nitrogen, ammonia, total (mg/L as N) 00610 Nitrate, as N Nitrogen, nitrite plus nitrate, dissolved (mg/L as N) 00631 minus nitrite,2 as N * Nitrogen, nitrite plus nitrate, total (mg/L as N) 00630 minus nitrite,2 as N * Nitrogen, nitrate, dissolved (mg/L as N) 00618 Nitrogen, nitrate, total (mg/L as N) 00620 Nitrogen, nitrate, total (mg/L as N03) 71850 (multiplied by 0.2259) Total nitrogen Nitrogen, total (mg/L as N) 00600 Nitrogen, total (mg/L as N03) 71887 (multiplied by 0.2259) Nitrogen,3 ammonia plus organic, total (mg/L as N) 00625 plus nitrate? as N, plus nitrite? as N **, * Orthophosphate, as P Phosphorus, orthophosphate, dissolved (mg/L as P) 00671 Phosphate, Of tho, dissolved (mg/L as P04) 00660 (multiplied by 0.3261) Phosphorus, orthophosphate, total (mg/L as P) 70507 Phosphate, total (mg/L as P04) 00650 (multiplied by 0.3261) Total phosphorus Phosphorus, total (mg/L as P) 00665 Iprom the USGS National Water Information System (NWIS) and the USEPA Data Storage and Retrieval system (STORET). 2Missing values or values less than detection are not included in this calculation. 3 Also called total Kjeldahl nitrogen. If value is missing or less than detection, total nitrogen is not computed. SURFACE WATER Water-quantity, water-quality, streambed- sediment chemistry, and tissue-chemistry data were available for 37 sites in the Gore Creek watershed. These data and information were used to evaluate the historical and current water-quality conditions. Predominant natural and human factors affecting surface-water conditions were identified to the extent possible. Water Quantity The major tributaries of Gore Creek are Black Gore, Bighorn, Pitkin, Booth, Mill, Middle, and Red Sandstone Creeks (fig. 1). The hydrologic characteris- tics of the Gore Creek watershed can be represented in a generalized water budget (table 3). This generalized budget provides an understanding of water storage and flux through the watershed. Average annual water input for the watershed is 185,000 acre-ft, based on an average annual precipitation of 34 inches distributed over the drainage area (Colorado Climate Center, 1984). Because the Gore Creek watershed is a headwater system, there are no surface-water inflows to the watershed except for an estimated maximum of 500 acre-ft/yr of water from the Eagle River for snowmaking (assuming snowmaking for all of November and December) (Jim Roberts, Vail Associates, oral commun., August 1998). This diver- sion into Gore Creek is highly variable, depending upon the needs for snowmaking, air temperature, and availability of other sources for snowmaking. The remaining water inputs by interbasin-water trans- fers and ground-water inflow are negligible. Water outputs from the watershed are more diverse; the predominant output is by surface-water outflow, which accounts for about 55 percent of the total water output. Evapotranspiration, which is calculated as the residual in the water balance, accounts for about 40 percent of the total water output. Consumptive water use, esti- mated to be 9,300 acre-ft/yr based on 1995 water- use data, accounts for 5 percent of the total water output (R.G. Dash, U.S. Geological Survey, written commun.,1998). 20 Gore Creek Watershed, Colorado-Assessment of Historical and Current Water Quantity, Water Quality, and Aquatic Ecology, 1968-98