Waste not, want not: the argument for xeriscape

 

By Katherine Eissler

 

With an average annual rainfall of 20 to 32 inches, increasing from west to east across the Río Grande Valley, there is little room for wasteful water habits, particularly on the edge of the Chihuahuan Desert where the primary source of water, the Río Grande, is a dwindling resource for municipal water supplies for millions of Texans.

According to the United States Geological Survey, diminished flows and water quality changes in the river from Ft. Quitman to the Amistad Reservoir, which is at 57 percent of conservation storage capacity, are due to development and drought conditions in the Río Grande Basin, and have caused stress on the watershed ecosystem and the riparian habitat.

Given our diminished resources for water and the need for conservation, it would behoove us all along the Río Grande to stick to prickly pear and yucca plants for landscaping. Fortunately, a host of beautiful low maintenance, drought resistant plants fit the bill for xeriscape -- a landscaping concept that maximizes water use while maintaining an aesthetically pleasing and environmentally sound surrounding.

There are many definitions for xeriscape, but generally it is defined as drought tolerant, low maintenance landscaping that incorporates some, or all, of seven principles -- planning and design, soil analysis, practical turf areas, appropriate plant selection, efficient irrigation, use of mulches, and appropriate maintenance.

There are several good examples of xeriscape throughout Laredo, most notably the campus of Texas A&M International University, which has incorporated motts or mogotes of native foliage -- mesquite, prickly pear, huisache, lantana, salvia, and verbena -- into the campus design.

Native plants such as perennial hibiscus and esperanza are fixed throughout the Lamar Bruni Vergara Gardens on the TAMIU campus, along with non-native yet drought tolerant plants such as dwarf Poinciana (a Caribbean shrub), plumbago (a South African evergreen), and hamelia (Texas fire bush).

Although 90 percent, or 125 acres, of the campus is covered in grass, it is mainly Bermuda , an African grass that has amazing resiliency and the ability to survive with very little water. It has a deep root system, and in drought, the root system can grow 47 to 59 inches deep. During dearth times the upper parts die off, but the grass keeps growing from its rhizomes, or rootstalks. Buffel grass was considered as a landscaping option, but it would have been unable to endure the high campus traffic.

“On weekends people come to the campus to hang out because the city parks aren't big enough and don't provide open areas to play in,” said TAMIU's Physical Plant director Richard Gentry.

Eighteen of the 125 acres are solely used as playing fields, and the only area in which TAMIU utilized a water-needy grass, St. Augustine , is in the center courtyard where graduation ceremonies are held.

By employing xeriscape techniques, being vigilant about water use, and with some help from the weather, TAMIU was able to save 35 percent on irrigation in 2003. Gentry said he hopes to further cut costs by updating the existing system and utilizing a computer-operated irrigation system that provides a more accurate measurement of water needed to maintain the grounds. According to Gentry, TAMIU is considering connecting to the city's wastewater effluent line as a source of irrigation.

The City of Laredo is in the process of applying for a permit from the State of Texas and the Texas Commission on Environmental Quality to increase the size of the North Laredo Wastewater Treatment Plant by one million gallons per day. The Lake Casa Blanca golf course and the Laredo Country Club golf course are currently using almost 100 percent of the plant's one million gallon per day discharge, which leaves little room for TAMIU to tap into, said City Engineering Manager Pablo Martinez.

“We are currently looking at offering effluent at half the cost, but we would have to amend the permit once we receive it to include other entities such as TAMIU,” said Martinez. Once the permit is approved the city will be on an 18 to 24 month timeline for the design upgrade.

According to City Manager Larry Dovalina, city officials have determined that the greatest draw from the Río Grande is from agriculture, accounting for about 90 percent of all water taken from the river, and much of that water, he said, is wasted due to outdated irrigation systems. City staff is actively upgrading the current irrigation ordinance to curb wastefulness by farmers and other large users.

The city manager said residential automatic sprinkler systems are much more efficient than hand-hose watering, but these systems must be maintained in order to prevent runoff into streets, which can seep under the pavement and cause potholes.

Despite an obvious need for a water conservation program within the city, city entities appear to be doing very little. The faint cry for water conservation is usually heard only when political candidates are grilled by green forums like the Río Grande International Study Center . Leading by example and incorporating xeriscape into landscape design for city buildings and parks would not only conserve the citys water source but would also save residents the tax dollars allocated for water usage at city facilities.

There are no broad examples of xeriscape at city facilities except for the occasional use of native trees around recreational areas. At three of the corners surrounding City Hall, sage and firecracker bushes frame the bus stop waiting areas. Across the street, the old Webb County Court House has both good and bad examples within the same block. Native anacahuita trees and cenizo grace the bus kiosks, but expanses of carpet grass likely consume the water that anacahuitas do not.

Dovalina said there are possible funds available to provide a xeriscape demonstration area within the city to inform residents of the countless options in xeriscaping and its money saving capabilities.

The city is also trying to promote water conservation by requiring increased plumbing standards in new homes, i.e., flush-efficient toilets. There is no full-blown plan for water conservation, said Dovalina, adding he does not believe that implementing a conservation plan would save a significant amount of water -- hard words for anyone who laments that the Río Grande no longer flows to the Gulf of Mexico.

Other cities in the area that have implemented a conservation plan have been successful. San Antonio has cut usage of gallons used per person per day by 32 percent since beginning its conservation program in 1984, according to a 2002 Laredo Morning Times article.

San Antonio Water Systems offers incentives to promote conservation, giving its customers $10 per square foot to convert St. Augustine grass to native grasses and $100 returns for water-efficient washing machines and toilets. They also offer $150 rebates on hot-water-on-demand systems, which can save up to 10,000 gallons a year per household.

Though Laredo Community College made some excellent attempts at establishing xeriscape practices on the main campus several years ago -- particularly around the art building -- those efforts appear to have gone by the wayside. The green-built (hay bale construction) Lamar Bruni Vergara Environmental Science Center on the campus still showcases natives that include mesquite, palo verde, cenizo, esperanza, and ebony trees.

The newly completed, newly landscaped South Campus of LCC will likely face some stiff water bills. Rather than clear only for the footprints of the buildings, all native brush was cleared and the land peeled back to zero vegetation to build the campus and its parking lots. Neither xeriscape nor water conservation appear to be on the agenda of those who make decisions for the school's operation.

The hillock that borders Hwy. 83, once covered with native foliage, is routinely watered -- often flooded -- so thoroughly in 100 degree-plus weather that run-off pools at the base of the hill and flows into a culvert, testimony to a water management plan that has no conservation component.

A recent open records request made by LareDOS for water usage at the south campus was answered by LCC president Ramon H. Dovalina, who said that LCC's construction contract requires the contractor to pay for water until the landscaping is complete. Dovalina said they have not been billed, but he estimates an average cost of $750 for the monthly irrigation of grass, elder pines, red oaks, live oaks, and crepe myrtles.

A good example of residential xeriscape can be seen at the Plantation subdivision home of Matilde Frank. That landscaping scheme is predominantly native grasses and trees -- buffel grass, Parkinsonia or Jerusalem thorn, palo verde trees, mesquite, acacia, and sago palm -- which require very little watering. Some of the plants surrounding the house require little or no maintenance and no water, other than that provided by Mother Nature. These are true examples of xeriscape.

The city's indifference to water conservation -- an indifference clearly delineated in public policy and in private practice -- poses some tough questions. What will be left of nature? What will become of us, we who depend on this sole source of drinking water? The answers reveal themselves all too slowly, nearly painfully.