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University of Texas at El Paso

 

walton"at"utep"dot"edu

 
  
 

 
 

 
 
Abubaker Alamailes Thesis

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
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residential home where some LID practices had been installed can store water for long periods of
time.