22 May 2009

Vegas Accounting

GOOD has a piece (via DW) on Lake Mead:
Las Vegas residents tried to pass a bill that would allow homeowners to install graywater systems but the Southern Nevada Water Authority blocked it, offering up a piece of fuzzy math as a defense. Las Vegas Valley is allotted 300,000 acre-feet of water per year from the reservoir. The water that goes down drainpipes in Las Vegas gets pumped 12 miles back to a reclamation plant near Lake Mead. This returned water counts as a credit toward getting more fresh water from the lake.

The Water Authority says if people start using graywater to water their lawns and gardens rather than using drinking-quality water, their lowered water bills will dissuade them from conserving water. In other words, the Water Authority believes that legalizing graywater will cause people to use more fresh water and return less dirty water to the reclamation plant.
First, the non-sequitur [in bold]: People install greywater systems to reduce their use (hence their bill). That's different from people who do not care, who may use more water if their bill goes down (because of some outside force). This another example of the "20/80 rule" -- 20 percent of the people care about how much water they use; 80 percent only care about their bill.

Second, the greywater issue is similar to SNWA's dependence on hook-up fees (more development) for revenue.

Basically, SNWA does NOT want greywater because it cannot charge for it. If greywater is NOT discharged into Lake Mead, LV cannot get a credit to take out more. If it cannot take out more, it cannot sell it to you, a person so impolite as to "cut out the middleman."

Bottom Line: Good ideas can die if they contradict the winners under the status quo.


WaterSource/WaterBank said...

The Southern Nevada Water Authority ( Las Vegas & Manager Ms. Pat Mulroy) do not want to allow the use of greywater for the same reasons that well permits in many areas are for in-house domestic use only.

"Vegas Accounting" is on a consumptive use ( CU ) basis.

Their central sewer system can be expected to have a depletion factor of approximately 5 percent.

That means if the average person uses 100 gallons per day, the effluent is treated and only 5 gallons are "lost" due to the sewage process (minimal evaporation).

After sewage treatment, 95 gallons are returned for a "credit" to allow 95 more gallons to be pumped from Lake Mead to supply more domestic demand/customers.

If the grey water were to be intercepted, the consumptive use would jump to near 80 percent. The domestic water user's C.U. would increase from 5 gallons to 80 gallons ... a 1600 percent increase !

The same is true for inhouse only domestic wells. They are permitted with the assumption that there will be NO DAMAGE because the C.U. is so small, but if the users intercept the grey water, the C.U. increases that same approximate 80 % each day. The accumulative affect of thousands of domestic wells is then substantial to the prior vested senior water right owners due to the depletion of groundwater.

Strangely, the Southern Nevada Water Authority cannot seem to formulate a way to receive information on how to keep Lake Mead reasonably FULL with NON-TRIBUTARY water and provide Las Vegas with DOUBLE their present water supply without the need to continually lengthen the straws ( suction pipes/pumps) into Lake Mead.

The SNWA would rather pursue a $4 Billion well field to extract water from the desert region NW of Las Vegas, which in all likelyhood will seriously damage the critical habitat in that whole region.

When Lake Mead is full, it holds 28.5 million acre feet and generates 2000 megawatts of RENEWABLE ENERGY worth $1 Billion a year.

At the present time, Lake Mead is holding only about 16 million acre feet. An additional ONE MILLION acre feet can be developed and stored in Lake Mead each year.

Part of that million acre feet could be instantaneously released to restore the Colorado River Delta valued at $2.4 a year by AZ University researchers. 68,000 acre feet could be released for recharge purposes into the old section of the All American Canal to keep Mexicali's 1.3 million residents from relocating in exchange for Mexico's enforcement of drug and immigration laws.

"Good ideas can die if they contradict", but the existance of these good ideas must continually struggle to shine through the sewage in hopes of being noticed.

WaterSource/WaterBank waterrdw@yahoo.com

WaterSource said...


Ooops ... left out a $Billion ...

"Part of that million acre feet could be instantaneously released to restore the Colorado River Delta valued at $2.4 BILLION a year by AZ University researchers."

Mister Kurtz said...

Even the eco-wonderland of Marin County does the same thing. Part of it is economic, part of it is the incredibly narrow focus that the good folks (and I mean that without sarcasm) who manage public water facilities acquire. If it's sewage treatment, flood control, what have you; by God, nothing shall stop them from their appointed rounds. They operate in little absolute fiefdoms, with a very narrow set of legislated responsibilities.

Post a Comment

Note: only a member of this blog may post a comment.