Water yield response to changes in land-use and climate in a semihumid/-arid transition region (Jinghe basin, Northwest China)

近几十年来，植被恢复对水土流失的控制是有效的，但也伴随着黄河主要支流水量的急剧减少。这导致了一场新的辩论，特别是关于森林发展的辩论。温度升高和降水量减少也可能导致产水量减少。制定土地使用和水资源综合管理办法的一个关键是了解和区分水文对土地使用和气候变化的反应。在这项研究中，从单棵树到流域的多个尺度，水平衡组成部分，植被结构动态和土壤水力特性将进行调查，并在选定的地块上连续监测该地区典型的植被。本研究将在黄河重要支流泾河半湿润/半干旱过渡区进行。我们遵循嵌套的方法尺度的地块和流域沿着上游/下游的情况下，在一个有代表性的子流域。在我们的测量的基础上，面向过程的模型BROOK 90将被用于预测水量对气候和植被变化的响应，这取决于地形和土壤条件。从地块研究中获得的结果将用于参数化分布式模型SWIM。下一步，SWIM将安装到集水区排放，并评估不同土地利用和植被管理对产水量的影响。这项评估将为通过森林管理恢复植被可以改变多少集水区提供坚实的基础，以维持一定程度的供水安全，确保更可持续的区域发展。

The effort of vegetation restoration in recent decades has been effective for soil erosion control, but accompanied by a drastic reduction of water yield in the main tributaries of the Yellow River. This has led to an emerging debate notably about forest development. Increased temperature and decreased precipitation may also have contributed to water yield reduction. An essential key for developing an integrated land-use and water management approach is to understand and separate the hydrological response to changes in land use and climate. In this study on multiple scales ranging from single tree to watershed, water balance components, vegetation structure dynamics, and soil hydraulic properties will be investigated and continuously monitored on selected plots with vegetation typical to the region. Our research will be carried out in the semihumid/-arid transition region of Jinghe which is an important tributary of the Yellow River. We follow a nested approach on scales of plots and watersheds along a upstream/downstream situation in a representative subbasin. On the basis of our measurements, the process-oriented model BROOK90 will be implemented for predicting the water yield response to changes in climate and vegetation depending on relief and soil conditions. The results obtained from plot studies will be used to parameterize the distributed model SWIM. In a next step, SWIM will be fitted to the catchment discharge and to assess the effect of different land use and vegetation management on water yield. This assessment will provide a solid foundation for how much of the catchment area can be changed by vegetation restoration through forest management to maintain a certain level of water supply security that will ensure a more sustainable regional development.