Lost Waterways: Clues From Digitized Historical Maps of Manila and Other Philippines Cities

Abstract

Abstract. We search for lost bodies of water in the cities of Manila, Tacloban, Iloilo, Cebu, Davao, and Naga by aligning their digitized Spanish-era and American-era maps to Google maps. These vanished ancient waterways can either become flooding hazards in case of extreme weather events, or liquefaction hazards, in case of earthquakes. Digitized historical maps of the cities were georectified, overlaid on current Google maps, and checked for potential missing bodies of water. Inspection through field visits and interviews with locals were conducted to verify the actual status of suspected sites. The validation identified lost, found, and even new bodies of water. There was also evidence of affected buildings, rainless flooding, and a “new normal” for the meaning of flooding among frequently inundated residents.

Environmental History of an Early Spanish Settlement in the Visayas, Philippines: Excavations in the Parian District of Cebu City | Kasaysayang Pangkalikupan sa usa ka Karaang Puluy-anan Katsila sa Kabisay-an, Pilipinas: Mga Nakubkoban sa Distritong Parian, Lungsod sa Sugbu

“…Hazards mapping for downtown Cebu (Figure 16) (Jubilo et al 2019) was done using historical maps and field inspections. Relict channels of the Guadalupe River and the Parian Estero were found digitizing historical maps and georectifying them with current Google maps.…”