y ▁tender ing ▁process , ▁work ▁began ▁in ▁January ▁ 2 0 1 0 ▁on ▁a ▁project ▁cost ed ▁at ▁£ 1 5 0 ▁million , ▁to ▁increase ▁the ▁capacity ▁of ▁the ▁res er voir ▁by ▁ 5 8 ▁per ▁cent , ▁and ▁to ▁upgrade ▁the ▁capacity ▁of ▁the ▁E ly - O use ▁Es sex ▁Transfer ▁Sch eme . ▁The ▁cl ay ▁core ▁of ▁the ▁main ▁dam ▁was ▁raised ▁by ▁, ▁to ▁allow ▁the ▁water ▁level ▁to ▁be ▁raised ▁by ▁, ▁increasing ▁the ▁surface ▁area ▁of ▁the ▁res er voir ▁from ▁ ▁to ▁. ▁The ▁original ▁p ump ing ▁station ▁which ▁p ump ed ▁water ▁to ▁L ayer ▁de ▁la ▁Hay e ▁treatment ▁works ▁would ▁have ▁been ▁sub mer ged ▁by ▁the ▁new ▁water ▁levels , ▁and ▁so ▁had ▁to ▁be ▁demol ished ▁and ▁re built ▁at ▁a ▁higher ▁level . ▁In ▁order ▁to ▁keep ▁the ▁system ▁oper ational ▁while ▁this ▁was ▁being ▁done , ▁a ▁temporary ▁p ump ing ▁station ▁was ▁built ▁on ▁the ▁shore ▁of ▁the ▁res er voir . ▁The ▁new ▁station ▁can ▁deliver ▁ ▁of ▁raw ▁water ▁per ▁day ▁to ▁the ▁works . ▁Other ▁enh anc ements ▁at ▁the ▁res er voir ▁site ▁included ▁the ▁construction ▁of ▁a ▁new ▁visitor ▁centre ▁for ▁the ▁Es sex ▁Wild life ▁Trust , ▁and ▁work ▁on ▁the ▁B 1 0 2 6 ▁cause way , ▁which ▁crossed ▁the ▁res er voir ▁at ▁a ▁height ▁where ▁it ▁would ▁be ▁below ▁the ▁level ▁of ▁the ▁new ▁water ▁surface . ▁ ▁With ▁the ▁capacity ▁of