an ▁nag ar , ▁Gand hin agar , ▁k as th uri ▁nag ar ▁p ud hu pe erk ad av u , k oth am ang al am ▁created ▁by ▁government ▁in ▁S ath y am ang al am ▁forest ▁near ▁b ann ari . The ▁government ▁then ▁started ▁to ▁build ▁the ▁dam . It ▁is ▁one ▁of ▁the ▁oldest ▁ear then ▁d ams ▁in ▁India . It ▁was ▁build ▁during ▁the ▁period ▁of ▁chief ▁minister ▁K . K amar aj . But ▁it ▁was ▁built ▁by ▁British ▁government ▁in ▁the ▁year ▁ 1 9 4 6 . ▁ ▁Dim ensions ▁The ▁dam ▁is ▁ ▁long ▁by ▁ ▁high . ▁The ▁full ▁res er voir ▁level ▁is ▁ ▁and ▁the ▁dam ▁has ▁a ▁capacity ▁of ▁. ▁ ▁H ydro graph y ▁B hav an is agar ▁dam ▁is ▁constructed ▁on ▁the ▁B hav ani ▁ ▁River . ▁The ▁dam ▁receives ▁water ▁from ▁two ▁main ▁catch ment ▁areas ▁in ▁the ▁Western ▁Gh ats . ▁The ▁water ▁is ▁fed ▁into ▁the ▁B hav ani ▁river ▁known ▁as ▁Upper ▁B hav ani . ▁The ▁eastern ▁catch ment ▁area ▁includes ▁the ▁Upper ▁B hav ani , ▁A val anche ▁and ▁Emer ald ▁la kes , ▁K und ha , ▁Ged hai , ▁P ill ur ▁and ▁Nell ith ur ai . ▁The ▁western ▁catch ment ▁area ▁includes ▁Port im und , ▁Par son ’ s ▁valley , ▁Py k ara , ▁Glen m organ , ▁Ch ink ara , ▁Mar av ak andy , ▁Mo yar