SUNDAY, FEB 22, 2015
Eric Lee, A-SOCIATED PRESS
TOPICS: GROUND WATER PUMPING, RAINWATER HARVESTING, FROM THE WIRES, GREEN LIVING, HISTORY
TUCSON (A-P) — For over 1,000 years Native Americans farmed the floodplain of the river near Tucson, which also supported many other natives. Water flow could be diverted to irrigate plots. Trees and grass prevented entrenchment of the riverbed, prevented it from cutting down and turning the river into a big wash. Pumping of groundwater started in 1881; the water table went down. Surface water went away; the river stopped flowing except to discharge storm runoff, and before long the water table was below the root zone of even the trees. The damn water-loving vegetation that was sucking up the water needed by the growing population (of humans and cattle) went away. Entrenchment was under way in the later part of the 19th century and was complete by 1912. Thereafter, entrenchment got deeper. Parts of the riverbed are now 30 feet lower. The water table is hundreds of feet lower, so there is only surface water after a storm.
The passing of the river, the death of floodplain life, should have been a sign. Business as usual should have been questioned. But pumping allowed continued growth. While some Colorado River water now recharges the aquifer near central Tucson where it is discharged, the drawdown continues. It's a "bigger you are, the harder you fall" situation. If falling harder is not good, continued growth isn't either. If pumping had stopped in 1912, or before, exponential growth would have been limited when there was about 15,000 people dependant on the railroad. Now one million are dependant on the railway and the highway.
To restore some flow in the river, whose bed is now much lower (so the water table will never be able to raise to it's former level), all pumping needs to stop. If all CAP water (Colorado River water), while it lasts, were discharged to soak in, the water table would raise faster than if only storm water recharges the aquifer. It may take a hundred years, but the damage can be partially undone. Since everyone agrees that Tucsonians need to transition to sustainable living, why wait? Just do it. Transition now. Stop pumping.
The City of Tucson can hire the highly recommended Brad Lancaster, rainwater harvester extraordinaire, to serve as consultant to tell them how to prosper on rainwater harvesting. Do so now while he is still available. Ask him, "How much can we offer you?" and double it.