FLOOD10357 - Laserfiche WebLink

Home Browse Search

! I' I I I I I I I I I I I I I I I I I I Alamosa River Watershed Project Literature and Watershed Assessment Alamosa River Watershed Water Resources 4.0 Introduction The most damaged resource in the Alamosa River Watershed is the Alamosa River itself. The river is the heart of the local community that depends upon the river for agricultural irrigation. Many of the people living in the watershed remember the river as an important recreational resource they used as kids for swimming and fishing. Significant impacts from the Summitville Mine operations and stream channel straightening by the Army Corps of Engineers have had an enormous impact on the river and the local inhabitants. This section provides an overview of the water quality condition in the watershed. Many of the water resource issues discussed pertain to all portions of the watershed such as general hydrology, water quality standards, total maximum daily load, etc. Water quality studies specific to a portion of the watershed can be found in subsequent sections of this report. 4.1 General Water Resources/Basin Hydrology The headwaters of the Alamosa River start in the upper portion of the watershed in the San Juan Mountains. The channel of the Alamosa River ends approximately 10 miles from the Rio Grande. The Alamosa River is not considered to be a tributary of the Rio Grande. Surface flows may reach the Rio Grande during flooding events such as the one that occurred in 1995. It is likely that there is a groundwater hydrologic connection between the two rivers (6). Figure 3 shows the Alamosa River and tributaries that comprise and define the Alamosa River Watershed. Most of the flows in the Alamosa River are stored in Terrace Reservoir for agricultural use. Over 51 ditches divert water from the river to irrigate farmland, pastures and to water livestock. For long periods of time each year, the Alamosa River near Capulin is devoid of water due to the lack of water releases from Terrace Reservoir, agricultural water withdrawals, and hydrologic conditions that recharge water to the underlying aquifer. The Alamosa River is characterized as a losing stream, as surface water at bankfull stage diminishes due to groundwater recharge. The bankfull width decreases downstream of Terrace Reservoir and eventually the Alamosa River disappears into a . large rift valley (19). 4.1.1 Gaging Stations There are only two gaging stations on the Alamosa River, both are near Terrace Reservoir. The United States Geological Survey (USGS) initially established a stream gaging station (#08236500) which is located approximately 0.5 miles below Terrace Reservoir. This stations are now maintained by the State of Colorado Department of 4-1