Marikina River - The Marikina River System

The Marikina River System

In Brgy. Wawa in Rodriguez, the Marikina River is dammed by Wawa Dam, a structure built during the early 1900s to provide water for Manila. From Rodriguez, the river flows through San Mateo then to its namesake city of Marikina. In Pasig City, the river meets the gates of the Manggahan Floodway, a controlled waterway used to prevent flooding in Manila during heavy rains by diverting most of the water of the Marikina towards Laguna de bay instead of Pasig River. Located 6.75 kilometres (4.19 mi) downstream is the confluence of Marikina and Pasig Rivers.

The river's depth ranges from 3–21 meters and spans from 70–120 meters. It has a total area of nearly 75.2 hectares and is 11 kilometers long. The riverbank has an elevation of 8 meters above sea level at the boundary of San Mateo and Marikina. This slowly goes down at an elevation of 4 meters nearly before the Malanday and Santo Niño boundary. The lowest elevation is along Calumpang which 2 meters above sea level.

Marikina River has 7 creeks and waterways connected to it. In the City of Marikina, this includes: Bankaan Creek which separates Barangays Parang and Concepcion Uno; a waterway known locally as "Ilog na Patay" (the dead river) which Separates the Barangays of Tumana and Concepcion Uno in Marikina, which is a remnant of the original path the river before it was redirected during the American Colonial Era to address the erosion problems the township used to face; and the Nangka River which separates Marikina from San Mateo, Rizal, and consequently, the National Capital Region from the Province of Rizal. In San Mateo, a notable tributary of the Marikina River is the Ampid River. On the Western bank of the river, in Quezon City, Pansol Creek in the Balara area, and the Calamiong Creek in Barangay Bagong Silang also empty into the Marikina River.