About Our Water
WATER SOURCES
The water supply system consists of three active wells, one obsolete well, two underground storage tanks, three distribution turbines, an electronic computer controlled center and chlorine/softening treatment unit. The aquifers below the district consist of the shallowest Dawson Aquifer (alluvial water), followed by the Denver, Arapahoe and Laramie-Fox Hills aquifers. All but the Dawson Aquifer are considered non- renewable or “non-tributary” water supplies.
The District has dual depletion adjudication rights to pump 183 acre-feet a year from the Denver and Arapahoe aquifers. An acre-foot of water covers one acre of land in one foot of water or about 326,000 gallons. Most of the water actually pumped due to availability, is from the Arapahoe formation, a deep aquifer where the water quality is very high. The District has two active wells reaching the Arapahoe aquifer, the Jordan (1990) and Carson II (2009) and one obsolete well, the Carson I, drilled in 1960 that is no longer unusable due to normal age related deterioration.
Finally, District has a small well in the Dawson aquifer with an augmentation plan allowing the pumping of up to about 30 acre feet per year. Dawson Aquifer water is considered renewable and therefore, the amount of water that can be pumped from the Dawson is contingent upon the amount of new water the District adds to the watershed through pumping from the Arapahoe and Denver aquifers.
The District used 26 acre feet of water rights it held Laramie-Fox Hills formation as a trade to increase its rights to draw Dawson water in 2001. The Laramie-Fox Hills water is 2,500 deep and thus expensive to drill into and pump from, and the quality is low being very high in dissolved minerals. Currently, the Arapahoe/Denver pumping rates between 25 and 30 acre feet to be drawn annually from the Dawson well. The Dawson aquifer is shallow and the water contains more dissolved minerals which to the end user, tastes more like "well water" but it is safe to drink. Dawson water is used mainly during summer months to help with irrigation needs. It is diluted with the very high quality Arapahoe/Denver water so the mineral impact is minimal.
East Valley does have an emergency inter-tie connection to the ACWWA water system that can only be used in emergency situations for short periods of time at a premium price. Each year the District complies with a comprehensive set of water quality tests required by the State of Colorado. This report is mailed to all customers, per State requirements, each year. Additionally, monthly quality tests on a smaller number of key potential contaminants are conducted to ensure water quality and safety.
LONG TERM WATER SUSTAINABILITY AND CHALLENGES
Long Term Water Sustainability and Challenges The Jordan and Carson II wells, East Valley’s primary sources, have dropped during the past few summers to a point where only about 70 feet of water is over the pump when it is running at full capacity (currently about 200 GPM), then “recovers” somewhat during the winter months. This recovery isn’t the result of new water entering the aquifer, but rather an equalization of overall aquifer water levels. Just over ten years ago, the Jordan well produced up to 600 GPM. Unlike a lake or pool of water, the water in the aquifer is held in sand and shale, much like a sponge where the “flow” or movement of water is held to a very slow pace. Water enters the well’s “cone of influence” and actual well cylinder at slower and slower rates as the aquifer drops. District managers and consultants suggest that pumping levels should not exceed 200 GPM to protect from a system failure and possible damage to pumps should the well cylinder run dry.
Small storage capacity also limits the District’s options. At 79,000 gallons, storage is about 100,000 gallons less than necessary to optimally manage the water supply at 200 GPM inflows. An additional 100,000 gallons of storage would improve irrigation time significantly, but would cost up to $250,000 dollars and has some risk of having little return value if the aquifer deteriorates to below 100 GPM -- a future difficult to accurately predict. East Valley has had discussion with all possible area water suppliers.
The Denver Water Board has not expanded its “blue line” for many years and even if Denver made water available, the cost to reach the nearest connection near Orchard and Havana is cost prohibitive. Aurora Water has been approached but has a long standing policy that ties added customers only to city annexations.
Aurora and Denver have instituted the “WISE” water sharing program with man larger south metro water districts, but the buy-in is costly, the water is not guaranteed in drought years and the current cost for treated water is $5.78 per 1,000 gallons. Currently East Valley can produce water with its wells at 1/3 that price. Cottonwood Water, located near E-470 and Jordan Road to the south, has been approached and could supply East Valley through ACWWA water lines, but like most providers, is unable to commit water sales outside their boarders for any long term period of time or at a cost lower than EV can produce water. Currently, the only available external water source is from the Arapahoe County Water and Waste Water Authority (ACWWA). ACWWA agreed in 2008 to sell us up to 50 acre feet of water a year at a cost close to what East Valley now charges customers for 95 acre feet. The Board believes that at this time, the most prudent course of action is to continue operating the system with a balance between conservation and reasonable water supply until ACWWA becomes a better option or other resources become available.
The District is also hopeful that as surrounding larger water districts begin developing renewal water sources such as northern supplies recently starting delivery to ACWWA and East Cherry Creek Valley, Parker’s Reuter-Hess Reservoir, Cottonwood numerous new surface sources and the WISE project, that the pressure on deep wells will be reduced allowing EV an extended period of water supply. It is uncertain when a major change will be needed, what the costs will be, or forecast the condition of ACWWA and other possible future water providers if, or when, the time comes that EV can no longer provide acceptable water supplies at acceptable costs.
