Cook Inlet Sediment Budget and Water Quality Model

Abstract

The topic that is being addressed is whether the sediment load into Cook Inlet increasing as the glacier melt rate has increased in the last 50 years? This is important since regional watershed understanding of the sediment balance and potential changes in sediment erosion and deposition rates in areas and along the coast may impact infrastructure like pipelines, bridges and roads, or communities. The scope includes a discussion on over fifty (50) years of related research, river water and sediment inputs, and an assessment of existing models. Data from USGS and other available sources were gathered, a large scale, high-level statistical assessment was conducted to determine if the riverine discharge data showed any significant increases in flow and sedimentation. The initial results showed that flow was increasing in time, and sediment transport could be as well. A more comprehensive review of the riverine discharge data shows a trend that the rivers are experiencing larger flows. There is not sufficient, comparable data yet to determine if the sediment load has also increased. The research efforts helped to create a basic sediment budget for the Cook Inlet Watershed. The most important results are that the glaciers are melting at a faster rate and the data show that the river discharge volumes are increasing, while sediment rates remain constant or are decreasing. The question this thesis is attempting to answer is whether there is also an increase in the sediment transport. Based on the available data reviewed, the river sediment load appears to be decreasing while the river water content appears to be steady or increasing.