Response and Recovery of Watersheds to Environmental Change

对人类引起的环境变化的日益关注， 强调需要更全面地了解 关键系统对变化的环境条件的反应。 需要更多知识的关系包括 水文系统对土地利用变化的响应 流域 本项目将分析流域的动态 上个世纪，在格鲁吉亚西南部， 森林砍伐发生在19世纪中后期， 复杂的沟壑和峡谷系统 然而，近几十年来， 该地区的伐木和农业活动已经减少 实质上，导致不太戏剧性但仍然重要的变化， 在径流制度。 该地区的实地考察将为以下方面提供信息： 更准确地确定土地使用干扰和河流反应的年代。 将对山谷填充物和阶地序列的沉积物样品进行年代测定 通过树木年代学和航空摄影分析。 土地利用 将使用税务记录和航空照片来确定变化。 数据 从这些调查将与地形和气候 使用修改的水文模型的数据。 该项目将有助于理论和经验 对河流地貌形成条件的认识 不稳定 它也将有助于对滞后的新知识 流域特征变化时的响应和恢复时间 通过人类活动。

Increased attention to human-induced environmental change has highlighted the need to understand more completely the nature and rate of responses of critical systems to changing environmental conditions. Among the relationships for which greater knowledge is needed are responses of hydrologic systems to changes in the land uses within drainage basins. This project will analyze the dynamics of watershed response to during the last century in southwestern Georgia, where rapid deforestation occurred in the mid- to late-1800s, leading to a deep, intricate system of gullies and canyons. In recent decades, however, logging and agricultural activity in the area have diminished substantially, causing less dramatic but nonetheless significant changes in runoff regimes. Fieldwork in the area will provide information for more accurate dating of land-use disturbances and fluvial responses. Sediment samples of valley fill and terrace sequences will be dated through dendrochronologic and aerial photographic analyses. Land-use changes will be identified using tax records and aerial photos. Data from these investigations will be related to topographic and climatic data using a modified hydrologic model. This project will contribute to both theoretical and empirical understandings of the conditions that promote fluvial geomorphic instability. It also will contribute to new knowledge about the lag times of response and recovery when watershed characteristics change through human activity.