Intercepting rain and stormwater using clay-sand liners to maximize irrigation to shallow-rooted plants in desert and arid areas

 

 

ABSTRACT: Harvesting rain and flood water is a common practice in desert and arid areas. The storage of water is always influenced by hot weather periods where most of the stored water is lost either by evaporation or infiltration of water into very deep aquifers.  Utilizing sand clay liners as barriers for near-surface material can work as an efficient tool for better use of water resources.  In desert areas where groundwater is located at a deep level the cost of retrieving water is high and requires expensive infrastructure and systems. The concept of this study is to create an artificial aquifer enhanced with pumping systems to supply water to shallow-rooted plants in an adjacent zone.  A simplified model consisting of major collection tanks with automatic pumps was used in a project to save irrigation water in the Eastern province of Saudi Arabia. This concept can be expanded to create large deep-seated storage overlain by granular soil to minimize evaporation. Water supply from this aquifer can be transported to nearby fields by gravity if the water level in the aquifer is higher than the planted area or by pumping if water is needed at a higher level. The sand-clay liner can be made up of bentonite of 10% to 15% clay content by dry weight. The work presented in this study includes the characteristics of the material used and the mechanism followed to retain and re-use water multiple times.  5TE Decagon sensors capable of recording moisture content, temperature, and electrical conductivity connected to Em50 data loggers were employed.  Chemical tests and the salinity of water were monitored during the process. Suggested storage geometries are presented for efficient use of the system.

 

 

KEYWORDS: subsurface storage, barriers, sand-clay mixtures, hydraulic conductivity, evaporation.