Misinterpreted Conservation Levels of Some Texas Reservoirs May Be the Reason the Experts Won’t Get Us Out of This Drought

I keep wondering if the drought is over for the longterm; there’s no question about the short term.  Despite all the wet, the U.S. Drought Monitor* has kept our area (Harris County) in the moderate and severe drought categories for some time.  This monitor, put out by a number of governmental agencies, uses many factors, such as climate changes, ground moisture, and lake levels, to indicate current and predict  future drought conditions.  With all this in mind, I have started to look at sites that indicate the levels and capacities of lakes across Texas since more rain has come.  (Check here if you too are interested.)

By looking at the charts, one can notice that lakes in the middle part of Texas are quite low, especially Lake Travis and Lake Buchanan.  However, many lakes in southeast Texas, which has had considerably more rain, are at 100% conservation level or nearing conservation capacity.  If the lakes are full and the ground is saturated, why are we still considered as being in a drought zone?

Possibly, some of those making these designations may only be looking at figures on lists and not looking at how some reservoirs function and the amount of water they generally contain.  For example, I live very near

The dike-like Addicks Dam extends for nearly 12 miles.

Addicks Reservoir, which is located west of Beltway 8 and north of I-10 in Harris County.  This reservoir, along with the corresponding Barker Reservoir on the south side of I-10, were built as flood protection for the city of Houston.  But to think of them as high dams with a lake behind would be a mistake.  The Addicks dam is more of a raised dike, L-shaped and running for about 12 miles.  Behind it are rough, wooded areas, some of which are swampy.  Highway 6 and Eldridge Parkway transverse this area from north to south, and Clay Road crosses it from east to west.  Bear Creek Park and Bear Creek Golf Club occupy some of the reservoir area.

An aerial view shows that behind the dam (highlighted in red) are wooded areas, not a water-filled reservoir.

Although there are some lower parts near the long dam that do hold water in the normally wet climate, the reservoir never reaches 214,150 acre-feet, which the Texas Water Development Board says is conservation capacity.  The reservoir’s record capacity was 60,190 acre-feet when nearly a foot of rain fell in the west Houston area.  After a 2009 storm, the exceptional amount of water in the reservoir covered park areas and roads as well as into homes in neighboring sub-divisions.  Even now, with the reservoir at only 3.5% of conservation capacity parts of Bear Creek part are inundated.

Despite the heavy rains that the gulf weather often brings, it would probably take some kind of Noah’s Ark storm to bring Addicks Reservoir up to conservation capacity.  If that were ever to happen, many of the developed areas surrounding it would probably flood too, because the terrain in is generally flat.  Therefore, if the climatologists who are determining the severity of this drought (now I would say so-called drought) are using the conservation capacity of Addicks Reservoir (and other similar reservoirs) as part of their calculations, they should look at them realistically, rather than just as a set of arbitrary numbers.

*A more optimistic view is shown by the Keetch-Byram Drought Index at Texas A&M’s Texas Weather Connection.

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