Quantifying and Predicting the Attenuation of Downstream Fluxes Associated with Beaver Meadows

预计美国大部分地区将出现变暖和干燥，这将对现有的消费活动用水供应以及生态系统的健康和恢复能力造成压力。美国西部的干旱和半干旱地区尤其如此，包括像科罗拉多州这样的源头州。鉴于预计该地区发生干旱和洪水的可能性会增加，保持并逐步从流域内的地表和地下蓄水区释放水的能力非常重要。本研究将评估含有大量水坝、池塘和多通道的海狸草甸的潜力，相对于没有海狸活动的河段，它们会大大减少下游的水、沉积物、有机物和硝酸盐的通量。这项工作的结果对于恢复河流功能、减弱洪水脉冲和增加低流量期以及减轻气候变化的潜在影响具有重要意义。在本研究中，研究者将(1)量化河狸草甸相对于贡献流域面积和草甸活动/空间异质性的下游通量衰减幅度，(2)评估流域内草甸位置如何影响下游衰减，(3)评估该地区景观变化的程度和幅度。(4)在更大的空间范围内估算景观变化对水文动态的潜在影响。将利用来自水文学和地貌学的定量跨学科方法来量化集水区形态、储存和通量之间的关系，并将这些动态扩展到更大的空间范围。该研究将对海狸草甸形式的保留区提供的缓冲能力提供新的见解，并就达到规模的行为影响流域规模过程的方式开发新的概念和数值模型。

Predicted warming and drying across much of the U.S. will stress existing water supplies for consumptive activities, as well as ecosystem health and resilience. This is particularly true for the arid and semi-arid regions of the western U.S., including headwater states such as Colorado. Given the predicted increased potential for droughts and floods in the region, the ability to retain and gradually release water from surface and subsurface retention zones within river basins is important. This study will evaluate the potential for beaver meadows which contain numerous dams, ponds, and multi-thread channels, to substantially attenuate downstream fluxes of water, sediment, organic matter, and nitrate relative to river segments without beaver activity. Results of this work will be important for restoring river function, attenuating flood pulses and augmenting low flow periods, as well as for mitigating potential effects of climate change.In this study investigators will (1) quantify the magnitude of downstream-flux attenuation as a function of size of the beaver meadow relative to the contributing drainage area and activity/spatial heterogeneity of the meadow, (2) evaluate how meadow position within a catchment affects downstream attenuation, (3) assess the extent and magnitude of landscape alteration in the region, and (4) estimate the potential influence of landscape alteration on hydrologic dynamics across larger spatial extents. Quantitative interdisciplinary methods from both hydrology and geomorphology will be leveraged to quantify relationships between catchment morphology, storage, and flux and to scale these dynamics to larger spatial extents. The research will develop new insights into the buffering capacities offered by retention zones in the form of beaver meadows and develop new conceptualizations and numerical models on the manner in which reach-scale behavior influences catchment-scale process.