Laguna de Bay
Although a 1991 study cited the San Pedro River and Morong River as the sources of eutrophication-causing minerals in Laguna de Bay, the Laguna Lake Development Authority (LLDA) has noted that more recent deterioration of the San Cristobal River in Calamba have made it one of the lake's major sources of nutrient loading. The LLDA's conservation efforts for the major tributaries and watersheds of Laguna de Bay have led to the creation of the Laguna de Bay River Basin Councils, of which the San Cristobal River Enhancement Defenders (SACRED) is particularly tasked with conservation of the San Cristobal.