Lewisville Expected to Have Mandatory Water Restrictions this Spring
Date 2012/2/22 8:45:17 | Topic: Local News, Notes and Events
Lewisville City Council members were told at the February 4th Council retreat that Stage 2 mandatory water restrictions would likely be implemented this coming April. Residents should keep this in mind when making their Spring nursery purchases for their lawns and gardens.
The City of Lewisville has no water rights of its own in area lakes, but instead must purchase water from Dallas Water Utilities, which owns the water rights to the City's namesake Lewisville Lake. Part of that water contract requires that if Dallas requests it, Lewisville must implement Stage 2 restrictions.
Lewisville has two primary sources of water, both from DWU: drawing raw water from Lewisville Lake to treat in the city's own water treatment plant, which is rated for a treatment capacity of 20 million gallons per day (MGD), or treated water from Dallas, which is subscribed to at a capacity of 9 MGD, for a total capacity of 29 MGD.
In 2011, Lewisville reached and temporarily exceeded its supply capacity to provide water, hitting a peak in August of 29.9 MGD, which was met partially by drawing down elevated storage. Lewisville's pumping system has a daily capacity of 39 MGD, which is what it could pump with current equipment if supply was increased.
Each additional MGD of capacity purchased from Dallas Water Utilities costs the city $200,000 per year - a fixed cost that cannot be avoided even if the city later reduces its demand.
2011 was a bad year for drought; even though recent rains have technically taken North Texas out of official drought status, over 60% of the state is still in severe drought or worse. Climatologists are concerned that a dry spring and hot summer could put us back into a perilous situation. Lewisville City Councilman Neil Ferguson says he is concerned that the recent rains could give residents a false sense of security.
Lewisville Lake is considered full when the water level reaches its "conservation pool" of 522 feet above sea level. Until recently, the lake sat as much as six feet below that level. Currently, Lewisville Lake sits at 521.18 feet, or 96% full. The lake can go as high as 532 feet to the top of the flood pool.
Exacerbating the situation for some area cities is a problem with invasive zebra mussels, a non-native species of bivalve that has infested Lake Texoma, causing officials to cut off transfers from that lake to Lake Lavon. Earlier this year, it was reported that zebra mussel DNA had been found in numerous local lakes, including Lewisville Lake, although it doesn't necessarily indicate that there is an infestations. Zebra mussels adhere to pipes, wreaking havoc with dams and pipelines unless steps are taken to prevent the larvae from attaching to them. The City of Lewisville doesn't expect a problem at its raw water intake from Lewisville Lake even if an infestation does occur, since the City pre-chlorinates the water as it enters the pipe.
Lewisville's water conservation plan has the following stages:
Stage 1: Water Watch Voluntary Conservation • Residential landscape watering only when needed, and only on scheduled garbage pickup days from 5 a.m. - 9 a.m. or 7 p.m. to 11 p.m. • Commercial landscape watering only on Wednesdays and Saturdays from 5 a.m. to 9 a.m. or 7 p.m. to 11 p.m. • No swimming pool draining and refilling. • No hosing off pavement, buildings, or windows • No operation of ornamental fountains • Restaurants should only serve water to customers who request it • Use shut-off nozzle when washing vehicles • No water use allowing runoff or other waste.
Stage 2: Water Emergency Mandatory Restrictions • All Stage 1 restrictions become mandatory.* • Commercial car washes may be limited between 2 p.m. and 6 p.m each day. • Water rates can be increased for residential users consuming in excess of 6,000 gallons per month.
* Foundation watering with hand-held hose or soaker hose are allowed. New homes and new businesses with new landscaping will receive a 30 day exemption to water new landscapes.
Stage 3: Water Crisis Mandatory Restrictions • All Stage 2 restrictions continue to be mandatory. • All landscape watering (both residential and commercial) is prohibited. • Car washing except at commercial car washes is prohibited. • Commercial car washes can only be open Monday, Wednesday, and Friday • Commercial users may be required to reduce water consumption by a determined percentage
Council members did have some discussion about implementing tiered water rates as a way of incentivizing water conservation, but no decisions have been made. Currently , all customers get the first 2000 gallons included in their base meter charge, and each additional thousand gallons is sold at a flat rate of $2.76. Under the current rate structure, when you account for the meter charge, in some cases large users can actually pay a lower effective rate per mgal than frugal users.
The rationale for using a tiered plan is that it not only encourages conservation, but that it more fairly assigns the costs for the increased water usage. The cost to provide water to residents consists of two main components: Actual water purchased, and capacity purchased. Since Lewisville's daily water consumption averages 13.25 MGD, and most of the increased usage in the summer can be attributed to outdoor watering, that extra 16 MGD of capacity is mostly attributable to those users. The logic is that this extra capacity cost should be paid for by those users instead of having all users pay the same rate, where frugal users effectively subsidize heavy waterers. More information about rate structures can be found on page 3 of this Texas Water Matters report.
Lewisville residents are, on average more frugal about water usage than residents of other cities, using an average of 176 gallons per capita per day (GPCD). In comparison, Flower Mound uses 236, Dallas uses 260, and Farmers Branch uses 329, Addison uses 421, but The Colony only uses 108. But most of these numbers are still well above the target goal for the region of 140 GPCD. The numbers are affected somewhat by the amount of industrial usage.
Here is the video from the City Council Retreat where Assistant City Manager Steve Bacchus delivers a presentation about the city's water production and conservation measures, and Council discusses the topic: