AIDC project number: RR11.02
William Schnabel
The lack of information about sediment delivery, both in terms of bed and suspended loads, from many Alaskan rivers is a fact recognized by the research community and state agencies. Information on sediment characteristics and sediment loads is not available in major rivers along the proposed road to Ambler. The Alaska Department of Transportation and Public Facilities (Alaska DOT&PF) proposes to build a highway from the Dalton Highway in the vicinity of Coldfoot, AK to the Ambler mining district in the vicinity of Ambler, AK. This project is performing hydrologic observation and evaluation on three rivers along the 200+ mile transportation corridor for bridge planning and permitting purposes. This work is similar in nature and scope to the current UAF work on the Alaska DOT&PF Foothills West project (aka, Road to Umiat). Similar to the region surrounding Umiat, the route to Ambler lacks the available environmental data (meteorological, hydrological, biological, etc.) necessary to support the bridge permitting and design process. This project is adding value to current hydrologic investigations along the proposed Ambler corridor. The research team has purchased field supplies necessary to intensively investigate sediment transport along the selected river reaches, one additional watercraft for collection of field data, and funded one graduate student to aid in the collection, analysis, and reporting of field data. As a first step, the project will carry out a basic measurement plan to quantify suspended sediment loads in some of these streams, and will install autosamplers (ISCO or similar) in the streams as well as turbidimeters. Sediment samplers will be deployed in the field soon after breakup, and will be retrieved in late fall. Samplers will collect daily water samples, suspended sediment concentration will be estimated in UAF research labs. Turbidimeters will be set to collect hourly data. Correlation between suspended sediment concentration from water samples and data collected by the sensor will be developed. The turbidimeter will provide information to identify and quantify daily sediment pulses. Additionally, bed sediment samples will be collected in each of the study sites. Giving the spatial distribution of this proposed project, the project will create a valuable data set on sediment concentration. This information could serve as baseline data for federal and state agencies involved in different phases (from design, permitting and construction) of this project. The team will also employ an inflatable catamaran (cataraft) to aid in the collection of field data. Based upon continuing field experience, the WERC team prefers the stability and reliability of this platform for in-stream work during discharge measurements. Powered by oars or outboard motor, the craft provides a versatile research platform useful for large and small streams during most stages of flow.
