"For every complex problem there is a simple solution; and it is always wrong."

H. L. Mencken

In his letter to the editor of the __Borrego Sun __and fliers appearing
around Borrego, R. D. McKee claims that "tamarisk are consuming more water than
all other consumers combined." He calculates that there are 9,900 tamarisk in
the valley and asserts that each tree consumes 4 acre-feet of water per year, or
a total of 39,600 acre-feet annually. He is wrong.

First of all, it is intuitively unlikely that a single tamarisk could consume 4 acre-feet of water per year when we know that an entire acre of irrigated, mature citrus with one tree every 20 feet actually consumes only about 3.5 acre-feet/year.

Second, it can be confirmed by observation that most or all of the water consumed by tamarisk that could have any effect on the aquifer is already included in the figures published by the BWD and, conversely, that very little, if any – let alone all – of it is over and above that amount as McKee asserts.

Third, McKee’s figures are likely skewed by the nature of the data available/not available about water use by tamarisk.

Finally, using "tamarisk water consumption" as a search string in Google, as
McKee suggests, returns a number of documents that suggest a tamarisk tree "**may****use up*** to* (emphasis added) 300 gallons of water a
day." None of those sampled indicated higher use than 300 gals./day. Even
assuming that McKee’s estimate of 9,900 tamarisk in the valley is correct and
allowing the contrary to fact assumption that each tree uses the maximum 300
gals./day every day, the total amount of annual water use by tamarisk is far
lower than his projections indicate. Even at an overgenerous 300 gals./day, each
tree would consume roughly one-third acre foot of water a year; so 9,900
tamarisk would consume at most only 3,300 acre feet per year, or less than one
twelfth of what McKee claims. And, again, this is based on an obvious
overstatement of tamarisk water use in Borrego Valley.

In sum, tamarisk obviously uses water – maybe enough to justify large scale removal. The cost of such removal, however, is high; so the cost/benefit ratio must be carefully calculated. The data available do not support such calculations. The BWD is looking at ways of getting more and better information.

The question of tamarisk removal deserves careful and informed consideration. It is not, however, a silver bullet that will eliminate the overdraft in one fell swoop; so it is a disservice to the community and serious efforts to deal with our increasingly dire groundwater situation to raise false hopes by portraying it as such.

3/25/06