Himachal Pradesh is a province in the mountainous Himalayan region in northern India. Its numerous rivers make it a major source for hydropower in a rapidly growing region—a boon to the state’s economy. But the region’s many steep canyons and gorges also create challenges for building typical hydropower reservoirs.
Unlike in flatter areas, where reservoirs can store water behind a dam and release it at a controlled rate to provide a steady power source, in dramatic landscapes like the Himalayas, there’s nowhere to build a reservoir.
Instead, engineers rely upon what’s called a run-of-river system, where water is diverted from a river into a power plant, and then channeled back into the river. Run-of-river systems are also cheaper and easier to build than traditional large dams. The downside to this system is that it’s vulnerable to high sediment concentrations, since there’s no reservoir for sediment to settle into. Another drawback is that when a river stops flowing, so does the power.
Yet another downside is that during flash floods, the power facilities have to shut down to avoid being damaged. There’s nowhere to store the water and no way to capture energy, so it flows away, untapped.
Problems with sediment and flow can be partially mitigated by investing in watershed conservation activities upstream, a new study shows.
The research, published last month in Environmental Science & Policy, shows that sediment flowing into rivers that feed hydropower projects could be cut roughly in half (44%), by paying people upstream to perform specific conservation activities in targeted areas. The paper details the team’s use of NatCap’s InVEST and RIOS software to model ecosystem services within five watersheds in Himachal Pradesh.
“The problem with completely cutting all of the forest in your watershed, is that when it rains you’re going to get all the flow right away,” said NatCap’s Adrian Vogl, the paper’s lead author.
“If you have forests, then you have that storage of water, and the potential for sustained production over time.”
The study is timely. The state government has recently implemented a payment for ecosystem services policy, developed in collaboration with the World Bank as part of an integrated strategy to promote green economic growth. These results could influence investments from this new program.
Key research partners in the project include the Himachal Pradesh Department of Forests; the Department of Environment, Science, and Technology; the Energy Directorate; the Hydrology, Irrigation and Public Health Department; and the Aryabhatta GeoInformatics and Space Application Center. During the collaboration, the team conducted hands-on workshops to train local technical staff and policymakers how to use NatCap’s mapping and modeling tools to answer the questions they care about.
“We wanted to empower the forestry department to be able to advocate for and show why it’s a sound economic decision for the hydropower and energy sectors to be investing in forest management,” Vogl said.
Co-authors include numerous NatCappers—Stacie Wolny and Perrine Hamel (based at Stanford University’s Woods Institute for the Environment), P. James Dennedy-Frank (of Stanford University’s Earth Systems Science), Justin Johnson, (based at the University of Minnesota’s Institute on the Environment), as well as local champion Anil Vaidya, of Himachal Pradesh’s Department of Forests and Urvashi Narain of the World Bank, who initiated the project.
A more detailed account of the project can be found in a 2015 report, put out by Wealth Accounting and the Valuation of Ecosystem Services (WAVES).
The project inspired the World Bank’s Urvashi Narain to initiate a similar project with NatCap in Nepal, using similar methods to look at watershed investments for the largest hydropower plant in the country.
“We’re trying to get infrastructure people to understand that their infrastructure sustainability is dependent on ecosystem services,” Vogl said. “It’s about insuring your investment in this infrastructure.”
Read the study:
Managing forest ecosystem services for hydropower production
Vogl, Adrian L., P. James Dennedy-Frank, Stacie Wolny, Justin A. Johnson, Perrine Hamel, Urvashi Narain and Anil Vaidya
Environmental Sciences & Policy 61: 221-229. July 2016. doi: 10.1016/j.ecoser.2016.03.004
Stacey Solie is the Communications Lead at The Natural Capital Project.