 The San Diego Creek watershed is about 80 percent of the total land draining into Newport Bay – one of the largest estuaries in Southern California – and contributes between 77 and 95 percent of the total fresh water inflow to the bay.The population of the Newport Bay watershed in 2000 was about 705,000, which is projected to grow to 730,000 by 2030.The primary urban land use in the San Diego Creek watershed (not including the rest of Newport Bay) is transportation and communications.