Number of reservoirs (lakes) in Jakarta-Bogor-Depok areas is decreasing from about 218 in 1970 to less than 100 in 2003. Sedimentation rate in the big lakes are very high reducing the storage capacity. Sentani Lake in Papua since 1999 silting up of about 5 m/yr, Tondano Lake in Sulawesi, the deepest level in 1970 was 50 m, now only 10 m [2].
Big cities experienced severe ground water level decreasing. In Bandung city, intermediate ground water level (< 150 m) decreases 0.12-8.76/yr, while deep ground water level (>
150m) decrease 1.44-12.48 m/yr. In Jakarta (the areas around Cengakareng, Grogol,
Cempaka Putih, and Cakung), ground water level decrease of about 17 meter. In other regions of Jakarta, decreasing ground water level forms a cone, where the deepest point reach 40-50 m below sea level. The area of cone increase by time. The land subsidence almost occur in whole area of Jakarta of about 10-100 m. In Semarang, Middle Jawa, and Nganjuk,
East Jawa the gorund water level decreasing is about 2 m/yr and 1-5 m respectively especially in dry season [2].
Spring discharge is also decrease. Spring discharge utilized by PDAM (Municipal Water Supply Enterprises) Bogor up to 2001, decrease 4–15% [16].