Kevin Vranes has a phud in Physical Ocean- ography and Cli- matology. He now studies sci- ence policy and politics at the Eloise Kendy and John Bredehoeft (both private hydrology consultants) have a nifty new paper in Water Resources Research titled Transient effects of groundwater pumping and surface-water-irrigation returns on streamflow. Eloise is a former Congressional fellow (making this the second time I've highlighted the science of post-Congressional fellowship researchers). She and I also collaborated on a series of articles about the political scene that appeared in Geotimes.
I'll let snippets of the abstract speak for the paper (with my bolds):
In surface-water-irrigated western valleys, groundwater discharge from excess irrigation sustains winter streamflow at levels that exceed natural flows. This unnatural condition has persisted for so long that hydrologists, water managers, and water users consider it to be normal. ... we show that increasing irrigation efficiency has implications beyond simply reducing diversions. Improving irrigation efficiency reduces fall and winter flows to a lower, but more natural condition than the artificially high conditions to which we have become accustomed. However, existing water users and aquatic ecosystems may rely upon return flows from inefficient irrigation systems. By strategically timing and locating artificial recharge within a basin, groundwater and surface water may be managed conjunctively to help maintain desirable streamflow conditions as land uses and irrigation practices change.
This work follows on similar good work Eloise has been doing in the past few years, mostly on Bozeman, Montana-area catchment systems and Montana water politics. You can read examples of her other groundwater science-meets-policy work here and if you get The Water Report, check page 14 of Issue #19 (I'd post it, except for the line at the bottom of each page: "Reproduction without permission strictly prohibited").
Comments
# 1 | Brian S. | August 14, 2006 12:02 PM
Similar issue in south San Francisco Bay - many of the streams either never made it through the fluvial deposits to the Bay, or were far more seasonal. Some cool historical maps have come out recently about this. Returning to "natural" isn't really an option here, and probably isn't desirable.
# 2 | John Fleck | August 14, 2006 12:54 PM
In the middle Rio Grande Valley of central New Mexico, the river's largest tributary - by far - is the city of Albuquerque's sewage treatment plant. We pump groundwater, use about half of it "consumptively" (I love the water geeks' langauage), clean the poop etc. out of the rest and dump it into the river.
# 3 | kevin v | August 14, 2006 1:34 PM
Missoula does something similar with groundwater. Pump it at the east end of town for consumption and recharge the treated sewage back into the aquifer at the west end of town. The Clark Fork (river that flows through the middle of town) flows east-west so it's not too big an issue, but only recently did grad students in UMT's geology department really nail down the flow fields in the aquifer.