Groundwater Study

Groundwater Study


>>ACCORDING TO THE U.S. ENERGY INFORMATION ADMINISTRATION, ARIZONA WAS ONE OF NINE STATES NATIONWIDE WHERE EMISSIONS ROSE BETWEEN 2000 AND 2015. BETWEEN THOSE YEARS, CO2 EMISSIONS INCREASED BY 5%.>>>WHILE MUCH OF THE FOCUS IS ON THE COLORADO RIVER WATER, MANY COMMUNITIES IN SOUTHERN ARIZONA RELY ON GROUNDWATER, AND IT’S ANOTHER SOURCE THAT IS AT RISK. A RECENT STUDY FOUND GROUNDWATER SUPPLIES NATIONWIDE FALL SHORT OF PREVIOUS ESTIMATES. WE LEARN MORE FROM THE FINDINGS FROM JENNIFER McINTOSH, ONE OF THE STUDY’S RESEARCHERS AND A HYDROLOGY PROFESSOR AT THE UNIVERSITY OF ARIZONA. HOW DID YOU CONCLUDE THAT OUR GROUNDWATER IS IN PERIL?>>GOOD QUESTION. SO WE INVESTIGATED THE DEPTH OF POTABLE GROUNDWATER ACROSS THE UNITED STATES, AND WE COMPARED THAT TO THE DEPTH OF EXISTING WATER WELLS. AND WHAT WE SHOW IS THE DEPTH OF THOSE WATER RESOURCES UNDERGROUND IS ABOUT HALF OF WHAT WAS PREVIOUSLY ESTIMATED IN EARLIER STUDIES.>>SOUNDS LIKE WE SHOULD BE CONCERNED.>>YEAH. SO WE NOT ONLY LOOKED AT THAT GROUNDWATER IS BEING DEPLETED FROM THE TOP DOWN, BUT WE ALSO INVESTIGATED HOW GROUNDWATER IS BEING DEPLETED FROM THE BOTTOM UP. SO WE THINK OF IT AS THE WINDOW OF GROUNDWATER RESOURCES THAT COULD BE USED FOR HUMANS OR AGRICULTURE IS SHRINKING BOTH FROM THE TOP AS WELL AS THE BOTTOM.>>THERE’S A TERM THAT IS IN YOUR RESEARCH THAT I WASN’T FAMILIAR WITH, BUT THERE’S FRESH WATER AND THEN BRACKISH WATER. WHAT’S THE DIFFERENCE BETWEEN THE TWO?>>SO FRESH WATER IS SOMETHING THAT WE WOULD DRINK, SO IT’S NOT VERY SALTY. BRACKISH WATER IS IMPORTANT TO CONSIDER BECAUSE IT’S SLIGHTLY SALINE, SO MORE SALTY THAN FRESH WATER, BUT LESS SALTY THAN SEAWATER. SO IT’S POTENTIAL WE COULD USE THAT BRACKISH WATER IN THE FUTURE AS WATER RESOURCES BECOME SCARCE. WE COULD DESAL NATE THAT BRACKISH WATER AND USE IT FOR DRINKING WATER. IN SOME CASES IT’S ALREADY BEING USED LIKE IN THE OIL AND GAS INDUSTRY. SO IT’S A WATER RESOURCE THAT WE SHOULD CONSIDER.>>WHAT ARE SOME OF THE CHALLENGES WHEN YOU CONTINUE TO DIG FOR WATER, THOUGH, TO FIND THESE RESOURCES?>>THAT’S A GOOD QUESTION. SO IT DEPENDS ON HOW DEEP THEY ARE. SO THAT’S SOMETHING THAT OUR STUDY WAS TRYING TO PROBE AND GET A SENSE OF HOW DEEP YOU COULD FIND THESE WATER RESOURCES. THERE’S ALSO QUESTIONS ABOUT HOW WE MIGHT BE ABLE TO EXTRACT THOSE WATER RESOURCES, AND SO HOW EASY IT IS TO GET THEM OUT OF THE GROUND. AND THAT VERY MUCH DEPENDS ON THE GEOGRAPHY. YOU KNOW, WHAT THE SEDIMENTS ARE LIKE UNDER GROUND THAT THESE WATERS ARE STORED IN.>>ARIZONA HAS A PRETTY DIVERSE GEOGRAPHY. ARE THERE SOME AREAS THAT ARE PERHAPS EASIER THAN OTHERS?>>IT VARIES ACROSS THE STATE. SO THERE’S SOME LOCATIONS WHERE THERE’S RELATIVELY SALINE GROUNDWATER CLOSE TO THE SURFACE WHILE THERE’S OTHER PARTS OF THE STATE, SAY IN THE TUCSON BASIN, THAT YOU MIGHT BE ABLE TO DRILL MUCH DEEPER AND FIND FRESH AND BRACKISH GROUNDWATER.>>ON THAT NOTE, WE HAVE SOME AQUIFERS THAT ARE MORE ROBUST THAN OTHERS, FOR EXAMPLE IN COCHISE COUNTY. WHAT ARE SOME OF THE FACTORS THAT CAN CONTRIBUTE TO THAT?>>I THINK THE ROBUSTNESS OF AQUIFERS HAS TO DO WITH NOT ONLY THE QUANTITY OF THE WATER, AND THAT AGAIN HAS TO DO WITH THE GEOLOGY AND WHAT THE AQUIFER’S CHARACTERISTICS ARE LIKE, HOW EASY IT IS TO GET THE WATER OUT OF THE GROUND, BUT ALSO WHAT THE SALINITY OF THE WATER IS. THAT’S SOMETHING THAT WE LOOKED AT IN OUR STUDY.>>THAT ALSO HAS TO DO WITH THE NEARBY MOUNTAIN RANGES. IS THAT CORRECT?>>THE NEARBY MOUNTAIN RANGES ARE INCREDIBLY IMPORTANT IN ARIZONA BECAUSE THOSE ARE OUR WATER TOWERS. SO THAT’S WHERE A LOT OF THE WATER INFILTRATES INTO OUR AQUIFERS.>>OVERALL ACROSS THE NATION, SOME OF OUR RURAL POPULATIONS ARE DECLINING, OR WHERE PEOPLE LIVE ARE DECLINING. DOES THAT HELP IN THIS CASE IN THAT REFERENCE, GIVEN THAT COCHISE, FOR EXAMPLE, IS GIVEN MORE RURAL. IF WE HAVE LESS PEOPLE LIVING THERE, THERE’S NOT SO MUCH PRESSURE PLACED ON THE AQUIFER.>>IN THE STATE OF ARIZONA, THE VAST MAJORITY OF GROUNDWATER DEPLETION IS FOR AGRICULTURE. SO IT’S ACTUALLY NOT DOMESTIC WATER USE. AND THERE’S HUGE AGRIBUSINESSES IN RURAL PARTS OF ARIZONA, AND WE’VE SEEN MAJOR DECLINES IN THE LEVELS OF GROUNDWATER THROUGHOUT ARIZONA IN THESE RURAL PLACES BECAUSE OF EXTRACTION OF THE WATER FOR IRRIGATED AGRICULTURE.>>I THINK SOMETIMES IN THE AGRICULTURE WORLD, THERE’S A CONVERSATION THAT IF YOU CAN AFFORD TO CONTINUE DIGGING A DEEPER WELL, YOU’LL HAVE MORE ACCESS. IS THAT A RIGHT ATTITUDE TO HAVE ABOUT THIS PROCESS?>>WELL, IT’S INTERESTING AND IMPORTANT TO TALK ABOUT BECAUSE WE CAN POTENTIALLY EXTRACT DEEPER GROUNDWATER IN THE STATE OF ARIZONA, BUT THAT GROUNDWATER IS FOSSIL, MEANING IT WAS RECHARGED THOUSANDS OF YEARS AGO. AND SO WE’RE EXTRACTING THE WATER. IT’S NOT GOING TO BE REPLENISHED ANYTIME SOON. SO YOU CAN THINK OF IT AS MINING GROUNDWATER.>>WHAT’S THE LEVEL OF REGULATION OVER GROUNDWATER RIGHT NOW? DOES IT NEED TO INCREASE OR EXPAND RIGHT NOW? IS THIS THE APPROPRIATE TIME TO TALK ABOUT THAT?>>WELL, POLICY IS NOT MY AREA. BUT LOOKING AT, SAY, IN CONTRAST, THE TUCSON BASIN, IT’S PART OF AN ACTIVE MANAGEMENT AREA, SO GROUNDWATER IS ACTIVELY MANAGED ALONG WITH HALF OF OUR WATER COMING FROM THE COLORADO RIVER. IN RURAL PARTS OF ARIZONA LIKE COCHISE COUNTY, THERE’S NOT THAT GROUNDWATER MANAGEMENT. AND IN THOSE AREAS WE’VE SEEN HUGE DECLINES IN REGIONAL WATER TABLES. TABLES.

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