Continuous Water-Quality Monitoring in Indian Creek Active

Introduction

Elevated suspended sediment levels can cause an adverse impact on the living resources and associated aquatic habitat of streams, rivers, and estuaries. These elevated suspended sediment levels may impair the growth of aquatic vegetation through reduced light levels, bury filter feeding organisms, reduce the habitat available for macroinvertebrates, and contribute to decreased fish populations.

In most streams, the majority of suspended sediments are transported during storm-flow periods (Wolman and Miller, 1960), while rainfall-induced surface-runoff processes are active. Unfortunately, it is during these runoff periods that the fewest suspended sediment data are generally collected. One promising new technology for improved suspended sediment determination involves the continuous monitoring of turbidity as a surrogate for suspended sediment concentrations. Turbidity measurements are usually well correlated to suspended sediment concentrations because turbidity represents an optical measure of water clarity and it is the presence of suspended sediments that directly influences this measurement of clarity. Continuous turbidity measurement has now become a more common field approach because it provides significantly more detailed and more accurate information on suspended sediment concentrations than previously possible.

As part of the Jewell Ridge Lateral Project, construction of a proposed pipeline will require a crossing of Indian Creek, near Cedar Bluff, Virginia. There is considerable concern associated with the potential impact of this proposed construction because Indian Creek has been listed as one of the state’s Threatened and Endangered Species Waters. The primary impact of concern is that the construction activity will cause elevated suspended sediment concentrations below the pipeline crossing. Elevated levels of suspended sediment could be detrimental to the habitat for threatened and endangered species in Indian Creek.

Objectives

The primary objective of the USGS monitoring effort will be to identify whether the construction of the Indian Creek pipeline crossings will adversely impact the sediment water quality in Indian Creek. To accomplish this goal, continuous real-time water-quality monitoring will be the primary focus of the effort.

Approach and Methodology

Continuous water-quality monitoring will be performed in Indian Creek, in the area upstream and downstream of the pipeline crossings. The study will be designed in such a manner that sediment inputs from the construction and boring activities associated with the pipeline installation can be documented. Continuous water-quality data offer a relatively new, sensitive, and powerful tool for evaluating changes in water-quality composition that are caused by a variety of environmental factors.