Adaptation of low impact designs to the desert southwest
A low Impact Development (LID) practices were used to design an Integrated Management Practices (IMP) system for a residential lot .The design was adapted to the Desert Southwest region based on twenty years of climate data including precipitation and temperature for three representative cities: El Paso, TX, Albuquerque, NM, and Phoenix, AZ. In order to capture stormwater runoff close to its source and to provide as much stored water as possible for plants, LID practices including bioretention cells and vegetated swales were applied throughout the lawn. The purpose of the design is to maintain the pre-development hydrologic characteristics of the site, and therefore not to increase (or decrease) the runoff amount after site development. This will contribute to reduction of the dependence on conventional stormwater management practices downstream. Meanwhile a passive rainwater landscape can be obtained where the water captured by the bioretention units will be stored in the soil and used by native vegetations (shrubs and trees) that will no longer need watering throughout the year once their root establishment period has passed. A water balance was conducted to determine how much green/lawn area can be sustained. The water considered in the balance is that which is available for the plant uptake with a range between the field capacity and wilting point of the soil. Since evapotranspiration is also an important parameter in the water balance, native plants with low water requirements (excellent drought tolerance) and deep-wide root systems were carefully selected for modelling and implementation. Simulation results show that 20% to 50% of crown green/total lot area can be covered depending on the tree to shrub ratio. The change in soil water energy (soil water content and soil suction) was monitored simultaneously in an urban site (residential home) and in a desert at El Paso using, respectively, TDR (Time-Domain Reflectometry) and a soil moisture tensiometer. The collected measurements show that soil at residential home where some LID practices had been installed can store water for long periods of time.^
Environmental Management|Engineering, Civil
Abubaker Ali Alamailes,
"Adaptation of low impact designs to the desert southwest"
(January 1, 2011).
ETD Collection for University of Texas, El Paso.