New “source-to-tap” framework exposes and fixes mismatched use of water resource from protected areas

Traditional water resource management frameworks often overlook the ecological origin of water, leading to unquantified value and misallocated distribution of high-quality water resources (HQWR) from protected areas. In a new study published in Water & Ecology, a research team led by Gengyuan Liu from Beijing Normal University developed a novel spatially explicit "source-flow-use" accounting framework.

"The framework aims to trace and quantify the supply and sectoral allocation of HQWR generated within protected areas, based on ecological functions rather than administrative boundaries," says Liu. "Using Hainan Tropical Rainforest National Park as a case study, the framework identifies HQWRs from protected areas and track their distribution across economic sectors, establishing a replicable metric to link water accounting with governance instruments such as ecological compensation and differentiated pricing."

In particular, the framework traces High-Quality Water (HQW) from its source in protected areas to its final sectoral endpoints. It integrates digital elevation models, hydrological data, and geocoded water-use information through four key modules:1) identification of core HQW-producing river systems, 2) estimation of runoff contributions, 3) spatial matching of water use and flow paths, and 4) differentiated allocation using hydrological distance decay models.

"Applied to Hainan Tropical Rainforest National Park, the framework reveals significant spatial disparities. The study quantifies substantial variation in the effective shares of HQW received by different terminal users, with the CR to major river basins ranging from 70.8% for the Changhua river basin to 16.7% for the Wanquan river basin," Liu explains. "Recognizing and addressing spatial disparities is crucial for enhancing the efficiency, equity, and ecological sustainability of HQW utilization across Hainan Island."

The spatial heterogeneity observed across the three major river basins indicates that uniform management strategies would be inadequate. The analysis also reveals a critical misapplication of HQW in sectoral allocation. "Over one-third of HQWRs is consumed by agriculture, while the industrial and domestic sectors—despite their higher water quality demands—receive disproportionately small shares," says Liu. "Approximately 52 billion m³ of HQWRs remains underutilized in terms of ecological and economic values, highlighting mismatches in distribution."

Based on the quantitative insights from the HQW allocation and CR analysis, the researchers integrated policy mechanisms. They advocated for differentiated compensation and pricing schemes based on CRs, where differentiated water pricing should reflect HQW's ecological value—charging premiums for low-value or high-pollution uses while incentivizing a shift to conventional sources. Further, they also called for basin-specific responses tailored to local conditions, such as promoting precision irrigation in agricultural basins while urbanized basins must prioritize domestic and ecological flows.

"Ultimately, the framework supports linking terrestrial HQW accounting with coastal ecosystem management and institutionalizes these approaches through integrated basin governance like China's River/Lake Chief System," Liu adds.

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Contact the author: Gengyuan Liu , liugengyuan@bnu.edu.cn

-State Key Laboratory of Regional Environment and Sustainability, School of Environment, Beijing Normal University, Beijing 100875, China

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