three of the fresh water rivers that enter benoa bay from the north originate in the agricultural heartland of bali and reach the estuary after travelling through the highly populated urban centre of denpasar. agricultural runoff is particularly high in nutrients from fertilisers and manure from farm animals. in particular crop applications of urea, triple super phosphate and potassium chloride, as well as growth stimulant za are common in the catchment area. fertilisers that are not directly absorbed in the rice fields are carried down through the irrigation system and eventually through rivers and out into the bay. all of the rivers entering the bay have large quantities of excess nutrients and the nutrient loading of the bay is evident with the visible growth of algae and uncharacteristic sea bed grasses.