Steinberger Nancy, Wohl Ellen
Department of Public Works, Utilities Division-Greenways City of Boulder, 1739 Broadway, P.O. Box 791 Boulder, CO 80306-0791, USA.
Environ Manage. 2003 Jun;31(6):724-40. doi: 10.1007/s00267-003-2838-4.
Field investigation conducted on Boulder Creek in Boulder, Colorado evaluated impacts of flood control maintenance activities on flood conveyance, water quality, and fish habitat. Thirty-nine transects were monitored at one control site and two maintenance sites over a period of eight months. Each site was visited on more than 50 occasions in order to characterize pre- and post-maintenance conditions, and to monitor maintenance activities. Measurements along the transects included substrate composition, flow depth, velocity, and elevation. Reach-average values were assigned to variables such as in-stream vegetation, streambank stability, and woody vegetation before and after maintenance. Water temperature, dissolved oxygen, pH, specific conductance, and turbidity were sampled, and habitat suitability indices were developed pre- and post-maintenance for seven indicator fish species. Water quality impacts during maintenance consisted of high turbidity levels (> 400 NTU), which retumed to background levels (0.1-15 NTU) overnight, as well as changes in mean temperature and pH. Alteration of physical channel characteristics as a result of maintenance had limited effects on habitat quality for four of seven fish species, but caused improvements in habitat quality for three fish species. The main implications of this study for floodplain management are that: (1) Flood control maintenance practices can be in direct conflict with water quality and fish habitat objectives, and should be carefully designed and implemented by an interdisciplinary team. (2) Physical habitat for some fish species can be improved as well as reduced by maintenance activities. Habitat suitability curves may be useful tools for evaluating limiting factors of the habitat and for identifying opportunities for habitat improvements as part of maintenance.
在科罗拉多州博尔德市的博尔德溪开展的实地调查评估了防洪维护活动对洪水输送、水质和鱼类栖息地的影响。在八个月的时间里，对一个对照站点和两个维护站点的39个样带进行了监测。每个站点都进行了50多次访问，以描述维护前后的状况，并监测维护活动。沿样带的测量包括基质组成、水流深度、流速和海拔。在维护前后，对诸如溪流植被、河岸稳定性和木本植被等变量赋予河段平均值。对水温、溶解氧、pH值、电导率和浊度进行了采样，并在维护前后为七种指示鱼类制定了栖息地适宜性指数。维护期间的水质影响包括高浊度水平（>400 NTU），其在一夜之间恢复到背景水平（0.1 - 15 NTU），以及平均温度和pH值的变化。维护导致的物理河道特征改变对七种鱼类中的四种的栖息地质量影响有限，但对三种鱼类的栖息地质量有改善作用。这项研究对洪泛区管理的主要启示是：（1）防洪维护措施可能与水质和鱼类栖息地目标直接冲突，应由跨学科团队精心设计和实施。（2）维护活动可能会改善也可能会降低某些鱼类的物理栖息地。栖息地适宜性曲线可能是评估栖息地限制因素以及确定作为维护一部分的栖息地改善机会的有用工具。
