Water security, or the ability to safeguard adequate and safe water for ecosystems, is critical to sustainable economic development and poverty alleviation. As climate change alters the hydrology (rainfall patterns, river flows, and water storage) of a specific area, environmental managers, water utilities, and other government officials need to understand, plan and manage their water resources to ensure water security in the future.
In response to the need to promote evidence-based planning for water security, the USAID Safe Water Project has embarked on hydrologic studies for 65 watersheds in Palawan, Negros Occidental, and Sarangani. These studies provide significant information such as total potential available surface water and groundwater recharge volume at baseline period and at the 2020 and 2050 climate change scenarios (RCP 4.5 and RCP 8.5), and locations of high recharge zones within each watershed. These will equip Safe Water-assisted provinces with the scientific evidence and understanding they need to improve water security in their provinces, even in the face of climate change.
Among the findings of the USAID Safe Water’s hydrologic studies are the following:
➡️ Available water will decline in the next three decades due to climate change
The volume of dependable flow in major watersheds will be further reduced. Sarangani will be the most affected, with its surface water flow reduced up to 18% while the Montible watershed in Palawan will be adversely impacted, with a 14% reduction. Groundwater recharge will generally decrease in the 2050 climate change scenario by about 8.9% to 14.7% from the baseline period. Moreover, all three provinces are projected to experience drier dry seasons and wetter wet seasons.
➡️ Permitted water extraction in some watersheds is more than the available flow
For instance, the permitted extraction volume in Bago watershed is more than twice its dependable flow.
➡️ The forest covers of some of the watersheds, without any immediate intervention, will be completely lost in 10 to 20 years
Malogo and Bago watersheds in Negros Occidental are denuded at about 1,000 hectares annually while Siguel deforests at about 239 hectares per year.
➡️ High recharge zones are located downstream of the watersheds
Economic development activities in high recharge zones are expected to further exacerbate deforestation, contributing to further reductions in dependable flow and ultimately hindering long-term economic prospects.
These pieces of information will serve as critical inputs to the policy formulation, planning and regulation for water security. Local government units (LGUs) and planning and regulatory agencies can use this data to prioritize areas for reforestation or protection by focusing on areas with the highest groundwater recharge potential, improving long-term planning by matching permitting of water resource use with available resources, and increasing sustainability of water use through the strategic shift from depleted groundwater sources to surface water sources.
Safe Water has presented the results of these hydrologic studies to national government agencies such as the Department of Environment and Natural Resources (DENR), the National Economic and Development Authority (NEDA) and the National Water Resources Board (NWRB) and LGU partners and stakeholders in USAID Safe Water’s project sites. The findings are recognized as vital evidence to guide policy, planning, and investment decisions.
In Palawan, the results of hydrologic studies have been used to prepare the Local Watershed Conservation and Restoration Plans (LWCRPs) of Aborlan, Dumaran, Narra, Roxas, Quezon and Taytay, and the Integrated Watershed Management Plans (IWMPs) of Irawan and Montible. The Puerto Princesa Water District and the municipality of El Nido are developing high-level studies based on these results to guide them in developing new water sources.
In Negros Occidental, the hydrologic studies have been used as a guide in the formulation of LWCRPs of Bago, Calatarava and Hinobaan. They also find use as a main reference of a feasibility study for the provincial government’s surface bulk water supply project that will source water from the Imbang and Malogo rivers and the Negros Occidental Provincial Integrated Water Security Plan (PIWSP) for 2023-2030.
In Sarangani, the data produced by these studies serve as inputs to the LWCRPs of Alabel, Maasim and Malungon, the Integrated Watershed Management Plan of BMRB, and the Upland Conservation Management Plan of General Santos City. The province uses the data to draft the Sarangani PIWSP and develop its Reforestation Development Program - One Million Trees as a flagship project of Ronda Probinsya Para sa Kinaiyahan.
The hydrologic studies have revealed to us that a holistic approach for managing water resources is necessary to meet the water needs of the population, including those living outside the watersheds, while maintaining a stable and healthy ecological system to sustain the water resource. USAID Safe Water will continue to assist the national and local governments as it replicates and scales up this evidence-based approach beyond Safe Water’s target geographic areas. (USAID SWP/ Carla Grino)