▁the ▁San ▁Juan ▁River , ▁the ▁two ▁rivers ▁act ▁as ▁natural ▁d rain age ▁systems ▁by ▁receiving ▁and ▁con ve ying ▁Cal amba ' s ▁( and ▁Cab u ya o ' s ▁for ▁San ▁Crist ob al ) ▁liquid ▁was tes ▁and ▁storm ▁surface ▁run off ▁to ▁the ▁nearby ▁Lag una ▁de ▁Bay . ▁Both ▁rivers ▁are ▁very ▁poll uted ▁as ▁a ▁result , ▁thus , ▁affect ing ▁the ▁water ▁quality ▁of ▁the ▁lake ▁as ▁well . ▁ ▁Although ▁a ▁ 1 9 9 1 ▁study ▁c ited ▁the ▁San ▁Pedro ▁River ▁and ▁Mor ong ▁River ▁as ▁the ▁sources ▁of ▁e ut roph ic ation - ca using ▁min er als ▁in ▁Lag una ▁de ▁Bay , ▁the ▁Lag una ▁Lake ▁Development ▁Author ity ▁( LL DA ) ▁has ▁noted ▁that ▁more ▁recent ▁d eter ior ation ▁of ▁the ▁San ▁Crist ob al ▁River ▁in ▁Cal amba ▁have ▁made ▁it ▁one ▁of ▁the ▁lake ' s ▁major ▁sources ▁of ▁nut ri ent ▁loading . ▁ ▁The ▁LL DA ' s ▁conservation ▁efforts ▁for ▁the ▁major ▁trib ut aries ▁and ▁waters h eds ▁of ▁Lag una ▁de ▁Bay ▁have ▁led ▁to ▁the ▁creation ▁of ▁the ▁Lag una ▁de ▁Bay ▁River ▁Bas in ▁Coun c ils , ▁of ▁which ▁the ▁San ▁Crist ob al ▁River ▁En h ancement ▁Def enders ▁( S AC RED ) ▁is ▁particularly ▁task ed ▁with ▁conservation ▁of ▁the ▁San ▁Crist ob al . ▁ ▁See ▁also ▁▁ ▁Lag una ▁de ▁Bay ▁ ▁Lag una ▁Lake ▁Development ▁Author ity ▁