▁to ▁three ▁in ▁ 1 9 9 0 . ▁These ▁schemes ▁resulted ▁in ▁the ▁Four th ▁District ▁being ▁awarded ▁a ▁Bor ough ▁of ▁Boston ▁C iv ic ▁Design ▁Award ▁for ▁the ▁way ▁in ▁which ▁the ▁buildings ▁were ▁renov ated . ▁ ▁Navigation ▁ ▁Histor ically , ▁the ▁dra ins ▁were ▁used ▁for ▁importing ▁coal ▁to ▁the ▁f ens ▁and ▁export ing ▁agricult ural ▁produce . ▁They ▁are ▁now ▁only ▁used ▁for ▁pleasure ▁cru ising ; ▁this ▁is ▁restricted ▁to ▁the ▁summer ▁months , ▁for ▁between ▁October ▁and ▁April , ▁the ▁water ▁levels ▁are ▁maintained ▁at ▁a ▁low ▁level , ▁so ▁that ▁there ▁is ▁scope ▁to ▁deal ▁with ▁high ▁volumes ▁of ▁ra inf all . ▁Con sequently , ▁there ▁is ▁ins u fficient ▁depth ▁for ▁navigation , ▁and ▁operation ▁of ▁the ▁sl u ices ▁can ▁cause ▁rapid ▁changes ▁in ▁water ▁level . ▁Between ▁April ▁and ▁October , ▁their ▁function ▁is ▁to ▁provide ▁ir rig ation ▁water ▁for ▁agricult ure , ▁and ▁so ▁they ▁are ▁maintained ▁at ▁a ▁higher ▁level , ▁although ▁changes ▁in ▁level ▁can ▁still ▁occur ▁at ▁short ▁notice . ▁ ▁Anton ' s ▁G ow t ▁lock ▁is ▁, ▁but ▁although ▁a ▁boat ▁of ▁this ▁size ▁could ▁pass ▁through ▁it , ▁most ▁of ▁the ▁dra ins ▁are ▁in access ible ▁to ▁such ▁large ▁craft . ▁The ▁only ▁other ▁working ▁lock ▁is ▁at ▁Cow bridge , ▁which ▁is ▁, ▁and ▁gives ▁access ▁to ▁the ▁Ma ud ▁F oster ▁d rain , ▁en abling ▁boats ▁to ▁visit ▁the ▁centre ▁of ▁Boston . ▁From ▁Cow