Facts. Groundwater. The big problem. Issues. Consequences of Subsidence. How can we help? 2 major aquifers. Louanne Nutile Mitch Jacobs Sam Bejarano

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1 Facts Groundwater Louanne Nutile Mitch Jacobs Sam Bejarano 2 major aquifers Tucson Basin Aquifer and the Arva Valley Aquifer There are 4 well fields Central, Southside, Santa Cruz, and Arva Valley well fields Pumping has increased over years. Rate of pumping is higher then the rate of recharge. If we decided to fill Addition water gap starting in 2030, we would need to find or reserve of 13,223 AF/year of water. However if we spread the amount need over 40 years, starting in 2010, it would be 6612 AF/year The big problem Arizona has been pumping water from its aquifers faster then it is replenished by natural and artificial help As we continue to pump lower into the ground, the water quality decreases because it is mixed with dirt, salt, and rock. Pumping lower costs more money. Pumping ground water is destructive to land and causes subsidence. Issues Consequences of Subsidence Over 30,000 square miles of Arizona have been affected by some subsidence When the ground sinks, buildings and infrastructure do not cope well. If Tucson continues to over pump its aquifers it will be jeopardizing the structural and infrastructural integrity of the city itself. In fact, in 1988 subsidence in Pima County caused damages to the Central Arizona Project (CAP) canal. How can we help? The Bureau of Reclamation should collaborate with the local governments to create a tax reduction or agriculture subsidies for those who help use less ground water. Create a campaign to increase the awareness of this issue to others. Stop pumping at a higher rate than water recharge. Incorporate other water resources to meet water demand.

2 Tucson Surface Water Positive effects for Reopening This plant was designed to recycle agricultural runoff water that was too polluted and salty for use. Yuma Desalination Plant By: Mike Gelb Michelle Smekal Phil J. If Arizona official would agree on opening up the desalination plant it will produce an estimated twenty five billion gallons of three hundred ppm desalted water, which is about seventy six thousand seven hundred acre feet per year. Negative Effects for Reopening Reallocation of the Colorado River The reopening of the plant would be very expensive and would cost an estimated thirty million dollars to open, plus an additional thirty million a year to keep it running. Environmentalists argue that reopening the plant would destroy the wetlands that have been created in Mexico. It has been explored by San Diego to potentially pay Nevada to give up a portion of its share of the Colorado River. Nevada would then pay for the construction and operation of a seawater desalting plant in San Diego and San Diego would get to use all the water. In tern San Diego reduces the Colorado River water they use, and Nevada would be able to take an equal amount from Lake Mead. Distribution of the Colorado River Upper Basin The upper basin states distribute 7.4 million acrefeet yearly. These states include: Colorado, Wyoming, Utah, New Mexico, and Arizona. (Arizona receives 0.05 million acre-feet a year from the upper basin states) Lower Basin The lower basin states distribute the same amount of water yearly amongst themselves and include: California, Arizona, and Nevada. Arizona receives 2.80 million acre-feet yearly from the lower basin states. Conclusions Reopening Expensive to reopen and maintain. Produce 25 billion gallons of three hundred ppm desalted water. Reallocation of Colorado River Ideas explored by San Diego and Nevada to pay for a desalination plant in San Diego. Nevada ability to use water from lake Mead. Tucson could take same idea with a different city.

3 What role does it have in fulfilling Tucson s future water needs? What is reclaimed water? When water is used once, it is sent to the wastewater treatment facility where it is treated and made into effluent. Some portion of that is treated further and becomes reclaimed water. Reclaimed water is typically only treated via secondary water treatment. This means it is not potable, and cannot be used as drinking water. Reclaimed water is an interesting water b th l ti What CAN Reclaimed Water be Used For? Watering the landscape Golf courses Other stuff School landscapes Watering livestock Watering crops Toilet flushing Dust suppression This may seem like limited use, but each of these primarily Who Uses Reclaimed Water in Tucson? City and county parks! 16 golf courses! Many TUSD schools! THE UNIVERSITY OF ARIZONA Reclaimed water use IS expanding! Very few residential homes. =[ Less than half of Tucson s golf courses Can Reclaimed Water Fill in Tucson s Water Deficit? Problems Limited existing infrastructure. Infrastructure construction is costly and there are specific restrictions that are in place to prevent reclaimed water from contaminating drinking water. Public Perception Many people do not like the idea of toilet to tap projects, which would further treat wastewater to make it potable. Most options are high-cost. Options Treat the water further anyways and make it potable. This is a relatively expensive option. Mandate local service area businesses/residences use reclaimed water for their landscaping/toilets. This is an expensive option because of possible lost city income and infrastructure maintenance. Provide substantial government subsidies to encourage businesses or residences to use l i d t The Bottom Line Reclaimed water alone cannot fulfill the water deficit Tucson has. However, reclaimed water CAN offset current potable water where reclaimed water can be used instead. If a sizeable investment were to be made, with disregard to the cheaper alternatives, reclaimed water could easily meet the demands of the city of Tucson s non-potable water needs. We have the resources necessary to treat more water. Do YOU want to deal with the city being torn p to implement more reclaimed ater

4 Conclusion Because of the high costs and safety precautions that must be taken to considerably increase the reclaimed water systems in the Tucson Water service area, I don t believe it is reasonable to expect reclaimed water to fill the water deficit through Rainwater Group Stephen Whitney Tobie Owl David Robillard Results Results Redux By the year 2032 the Tucson area will face a water shortage increasing at a rate of AF of water per year, Through the year 2050, Tucson is expected to be 264,462 AF in water debt. It has been theorized that in order to pay off the water debt the rainfall of the Arizona area could be harvested on a yearly basis in order to limit the shortage. Currently Tucson receives approximately 12 of rain per year over the 290 square miles of the current and obligated Tucson water service area. Approximately 16% of Tucson s water debt could be harvested off of the rooftops of Tucson buildings. Another 34% could be harvested off of the landscape of Tucson s service area, making it possible to collect at least 50% of Tucson s annual water debt. Starting in 2010 would limit Tucson s water debt from increasing annually at a rate of acre ft/yr in 2030 to 331 acre ft/yr, where the Tucson area could possibly pay off their water debt simply through water harvesting by starting in the year 2010 Other Possibilities for Collecting Rainwater Snow melt from the Santa Catalina mountains Collecting water from solar panels Water collection is simple to accomplish through the usage of simple cisterns A 5000 sq ft typical roof top can collect 37,400 gallons at 12 of rain a year. Discussion!

5 The Return of the Discussion 61% of rain water returns to the atmosphere by evapotranspiration Due to the aridity of Tucson the percentage is much higher, therefore much less than 39% of our rainfall enters the aquifer if not detained in a closed system Rainfall collection should not take away too much from the aquifer system, as it is mostly collecting water that would otherwise be lost by evapotranspiration. Discussion Episode III The damming of the Rillito River would also be a major step in keeping water within the aquifer system Help to stop land subsidence caused by the over pumping and lack of replenishment of the aquifer systems FIN!