Laguna de Bay sediment group conducts meeting update on sediment sampling and other activities on target basins
May 12, 2022
The Japan side of the Laguna Lake Sedimentation Group initiated and spearheaded the meeting with the Philippine counterpart most particularly regarding sedimentation of the Laguna Lake, one of the target basins of the HyDEPPS-SATREP Project. The discussion involved plans for sample collection, data sharing and analyses, remote sensing and theoretical calculations among others. A Google Earth Engine (GEE) app developed by ICHARM, showing typhoon data on the target basin was also presented and demonstrated to the attendees.
Primarily faciliated by Dr. Naito Kensuke of ICHARM, the meeting was attended by Dr. Atsuhiro Yorozuya, Dr. Aida Kentaro, Dr. Nagumo Naoko, Dr. Menglu Qin, Dr. Harada Daisuke (all from ICHARM) and Ms. Shimizu (University of Shiga Prefecture) from Japan side. The Philippine side, on the other hand was represented by Dr. Patricia Ann Sanchez (Project Manager), Dr. Aurelio A. Delos-Reyes, Jr. (Group 2 Study Leader), Dr. Roberto Soriano, Dr. Eugene Herrera (UP Diliman Members) and Mr. Julius Angelo Galang (Project Assistant).
Dr. Yorozuya started with the General Overview of the study to be conducted in the Laguna Lake. It will be composed of 3 research components namely: sediment runoff, sediment transport and remote sensing on the two selected catchment for the first phase: Sta Maria and Pagsanjan.
Dr. Kensuke then presented the plans for data and measurements including parameters needed as well as methods to be used. Among these methods is surveying and sampling from a bridge. Dr. Soriano and Dr. Herrera then discussed details currently known regarding the two catchments (e.g. fineness and coarseness of sediments, baseflow, etc). They also remarked on the ease and possibility of finding a suitable bridge for sampling and surveying in each location. Finding the best bridges for the two catchments was then given as an assignment for the Philippine members. For other data and samples, the team is planning to collaborate with the Laguna Lake Development Authority (LLDA).
This was followed by the RSR (Rainfall-Sediment Runoff) model by Dr. Daisuke and Dr. Qin. The model considers sediment production, sediment transport and sediment sorting. It has already been implemented in Abira River in Japan with collected data for validation.
Ms. Shimizu discussed regarding lake shore energy flux which is defined as an index to evaluate sediment transport along the shoreline. Parameters needed to calculate include wind direction, wave height, etc. Dr. Sanchez remarked how lake current changes direction depending on the season and must be considered together with other factors that drive the current.
Lastly, Dr. Kentaro demonstrated the Google Earth Engine (GEE) app they have developed that shows a wide variety of data such as vegetation, typhoon, track, etc which is particularly useful for remote sensing. It aims to utilize existing satellites such as the Modis, Sentinel 2 and Landsat.
The team is set to have another meeting tentatively on June 16. Other topics and new updates on the study are to be discussed. A separate meeting will also be set with LLDA to formalize a collaboration agreement.