土地利用与覆被变化对流域水电生产影响研究—福建省九龙江流域为例

Measuring and Mapping the Impact of Land Use and Land Cover Change on the Hydropower Production—A Case Study of Jiulong River in Fujian Province

摘要: 水电是全球利用最广泛的可更新能源，其生产能力对土地利用/覆被的变化非常敏感。研究土地利用/覆被变化与流域水电生产的数量、价值及其空间分布的关系是流域水资源规划和管理的基础。本论文应用InVEST模型评估九龙江流域土地利用/覆被变化对水电生产数量及其价值的影响。结果表明：2000~2010年间，九龙江流域内，土地利用/覆被主要由蒸散量较大的耕地和林地转化为蒸散量较小的建设用地，产水量增加了0.66%。但由于耕地和建设用地的耗水量较其他土地利用/覆被类型大，水电生产的供水量却降低了8.46%，导致流域年均水电生产量减少1.22亿kwh，年均利润减少0.40亿元，减少幅度分别达到5.56%和6.69%。流域内水电生产数量减少主要是由土地利用/覆被变化大的城市子流域发电量减少引起的。模型验证结果显示，模型结果与实际产水量、发电量的误差分别在6%和5%以内，模型具有很高的可靠性。研究同时显示，九龙江流域产水量由上游向下游递减，上游子流域单位面积和万吨供水量水电生产的潜力最高，对流域水电生产的贡献最大，因此上游子流域的保护对流域水供给服务和水电服务能力的保障非常关键。

Abstract: As the most widely used form of renewable energy in the world, the hydropower production is very sensitive to the land use and cover change (LUCC). Measuring and mapping changes in the quantity and value of hydropower production are the basis of water resource management and watershed spatial planning. This paper evaluated the impacts of LUCC on the hydropower production in Jiulong River watershed (JRW) employing the reservoir hydropower production and valuation model of InVEST. The results show that the water yield increased by 0.66% from 2000 to 2010 in JRW since LUCC is mainly converted from arable land and forest with higher evapotranspiration to construction land with lower evapotranspiration. However, the annual water supply for power generation decreased by 8.46%, due to the water consumption in arable land and construction land are higher than other land cover type, which resulted in 1.22 × 10⁸ kwh decrease of the annual hydropower production and 4.0 × 107 yuan decrease of net present value separately. The reduction of hydropower production and its value are mainly located in urban subwatersheds whose land use cover change significantly by transforming the forest and arable land to the construction land. The model error is in the range of 6% and 5% of the actual water production and power generation respectively, and the model has high reliability. The results also show that the volume of water yield decreased from upstream to downstream, and the hy-dropower production capacity of subwatersheds in upstream is much higher than that of the down-stream. The subwatersheds in the upstream with higher water yield are critical to the water supply services in the JRW, which should be conserved when developing the spatial planning and other so-cial-economic planning in the watershed.