Test Drive | Page 178

Chapter  9:  Case  studies  in  Ta’izz     are   charged   more—more   than   $1/m3—if   the   crop   is   qat.     The   fact   that   well-­‐owners   sell   at   low   prices   to   neighbours   for   agriculture   and   at   much   higher   prices   for   the   tanker   market   does   seem   to   reflect   the   recognition  of  the  traditional  principles  of  local  cooperation  regarding  water  (Mounch,  2007).     Pollution  due  to  non-­‐treated  waste  water   The   population   growth,   municipal   and   industrial   activities   in   Ta'izz   city   have   resulted   in   the   increasing   deterioration   of   the   water   quality,   especially   in   the   shallow   groundwater   aquifer,   which   represents   the   principal   groundwater   resource   in   the   area.   Nearly   5   million   cubic   meters   per   year   of   untreated   wastewater  is  discharged  into  the  basin  system  through  the  septic  tanks,  stream  channels,  sewage  lagoons   and