ECOLOGICAL IMPACT ASSESSMENT OF RUN-OF-THE-RIVER HYDROPOWER PLANT: HYDROLOGIC AND HYDRAULIC MODELING COMPONENTS

ECOLOGICAL IMPACT ASSESSMENT OF RUN-OF-THE-RIVER HYDROPOWER PLANT:
HYDROLOGIC AND HYDRAULIC MODELING COMPONENTS

1.   Richmark N. Macuha Assistant Professor Institute of Civil Engineering University of the Philippines - Diliman       2023 UP COE PROFESSORIAL CHAIR COLLOQIUM “ Engineering Research and Development Towards Sustainable Development Goals” 25-27 January 2023 | UP National Engineering Center FEDERICO E. PUNO PROFESSORIAL CHAIR B       ECOLOGICAL IMPACT ASSESSMENT OF RUN-OF-RIVER HYDROPOWER PLANT: HYDROLOGIC AND HYDRAULIC COMPONENTS

2. INTRODUCTION Hydroelectric Power Plants: Uses renewable and clean energy source Flexible electricity generation, i.e., can quickly go from zero to max output unlike thermal plants More durable [over time] compared to other alternatives Typical setup of a run-of-river hydropower plant (source: https://www.energy.gov/eere/water/types-hydropower-plants)

3. INTRODUCTION Revised Policy on Granting Water Rights Over Surface Water for Hydropower Projects National Water Resources Board (NWRB) Resolution No. 03-0613 approved on March 2014 To support DOE’s thrust “to harness and maximize renewable energy as potential source of power to meet increasing demand” To address the concern that “ the previous allocation of water for hydropower projects reduces the optimum rated power capacity ” limits the production of existing hydropower plants discourages potential investors Possibility of granting water rights for hydropower projects requiring more than 80% dependable flow >>> significant increase of allowable volume to be used for hydropower production

4. INTRODUCTION Revised Policy on Granting Water Rights Over Surface Water for Hydropower Projects National Water Resources Board (NWRB) Resolution No. 03-0613 Schematic representation of a run-of-river hydropower installation in plan view (Anderson, et al., 2014).

5. INTRODUCTION Revised Policy on Granting Water Rights Over Surface Water for Hydropower Projects National Water Resources Board (NWRB) Resolution No. 03-0613 Bases for granting water rights: environmental/ecological study and sustainability plan. Water quality parameters must be within the NWRB-prescribed allowable values:

6. Research Goal Protect water-related ecosystems [Target 6.6] Achieve the sustainable management and efficient use of natural resources [Target 12.2] Integrate ecosystem and biodiversity values into national and local planning [Target 15.9] Take urgent and significant action to reduce the degradation of natural habitats[Target 15.5] Through research, provide valuable inputs towards achieving SDG targets related to environmental protection in the context of hydropower development

7. Research Objective Review, evaluate and validate the technical contents of NWRB BR 03-0613 by: Performing in-depth literature review related to the NWRB-prescribed allowable values of water quality parameters Applying the guidelines to a pilot study area Looking at the past and present water permit applications since the implementation of the board resolution

8. Pilot Study Matuno River Bambang, Nueva Vizcaya As a tributary of Magat River, Matuno River has a watershed area of 590 km 2 . Water from Mountain Province, Ifugao, and Nueva Vizcaya flows through the river. Approximately 700-m length of Matuno River will be affected by a proposed hydropower development

9. Methodological Framework

10. Parameterization Land / soil cover Geology Channel geometry Topography Meteorology River discharge Sediment discharge Calibration/Validation Basin discharge Baseflow discharge Surface runoff Sediment discharge Nutrient concentrations Contaminant discharge INPUT OUTPUT Nutrient Concentrations Field Data and HYDROLOGIC Modelling Analysis HYDROLOGIC Modeling Concept

11. Hydrologic Model Screenshot of HEC-HMS platform showing the rainfall hyetograph (lower left) and subbasins (right) of the Matuno catchment area

12. Parameterization Topography Discharges Channel x-sections Rainfall Water Levels Water Levels Calibration/Validation Water Levels Velocities INPUT OUTPUT Field Data and HYDRAULIC Modelling Analysis Inundation areas Velocities Inundation areas River profile HYDRAULIC Modeling Concept

13. Hydraulic Model Screenshot of hydraulic modeling platform showing the dialog boxes for setting up geometric properties and boundary and initial conditions

14. Results Comparison between field data and model results Historical and synthetic flow duration curve of Matuno River Calibrated rating curve of the hydraulic model using the derived rating curve from actual gaging station of Matuno River

15. Results Sample reduction in flow due to water diversion for hydropower plant. Average water depth decreased by 57.5% Average velocity decreased by 80.9% Minimum post-development water depths range: 0.17m-0.43m.

16. Results Impact of Land Use Changes Land Use % of Total Watershed Area Present Future Built-Up Area 5.79 18.17 Agricultural 26.54 60.73 Forestry 67.67 21.09

17. Results Impact of Climate Change Parameter Observed Baseline Change in 2050 Dec-Feb Mar-May Jun-Aug Sept-Nov Dec-Feb Mar-May Jun-Aug Sept-Nov Temperature ( C) 22.3 25.1 25.4 24.4 +2.0 +2.1 +1.9 +1.9 Rainfall (mm) 180.9 416.8 1149.8 880.5 -7.8% -23.6% +36.1% -0.5%

18. Summary NWRB BR 03-0613 aims to maximize hydropower production while ensuring the ecological integrity of rivers As required by the policy, detailed analysis of impacts supported by scientific data must be implemented Starting point of the ecological impact assessment is the H&H study as shown in the pilot area. Through H&H study, preliminary comparisons between predevelopment and postdevelopment conditions can be made. Likewise, the models can extend the assessment to other future scenarios, e.g., integrating impacts of climate and land use changes. H&H models can then be used as inputs to water quality models to address the stipulations from NWRB BR 03-0613.

19. On-going Works Liaising with NWRB to keep track of past and present water permit applications related to run-of-river hydropower development c/o J.B. Musico “Determining River Temperature Sensitivity to Hydraulic Parameters in the context of Run-of-River Hydropower Development” by D.H. Querubin “Impact Assessment of Run-of-River Hydropower Generation on River Sediment Yield” by G.P. Manio

20. REFERENCES 1. Afework, B. et. al. (2018). Run-of-the-river hydroelectricity. [Accessed Online: https://energyeducation.ca/encyclopedia/Run-of-the-river_hydroelectricity] 2. National Water Resources Board. (2013). Board Resolution No. 03-0613 – Revised Policy on Granting Water Rights Over Surface Water for Hydropower Projects. [Accessed Online: http://www.nwrb.gov.ph/ images/laws/BR_03-0613.pdf] 3. Wheeling Jesuit University. (2004). “Water Quality Assessment: Physical: Temperature”. Exploring the Environment: Water Quality, 316 Washington Ave., Wheeling, West Virginia, USA. [Accessed Online: cotf.edu/ETE/modules/waterq3/WQassess4h.html] 4. White, W.R. (1990). “Sediment Transport: The Ackers and White Theory Updated”. HR Wallingford, Oxfordshire , England. 5. National Water Resources Council. (1981). “ Magat River Basin Framework Plan”. Quezon City, Philippines. 6. US Army Corps of Engineers. (2016). “Hydrologic Engineering Center – Hydrologic Modeling System User’s Manual”. Davis, California, USA. 7. “Nueva Vizcaya Raster Digital Elevation Model”. n.d. Retrieved from [http://philgis.org/province-page/nueva-vizcaya] 8. US Army Corps of Engineers. (2016). “Hydrologic Engineering Center – River Analysis System User’s Manual”. Davis, California, USA. 9. Philippine Atmospheric Geophysical and Astronomical Services Administration . (2011). “Climate Change in the Philippines”. Quezon City, Philippines.