Relating Bedrock Strength to Hydraulic Driving Forces along the Large-Scale Profile of the Colorado River in Glen and Grand Canyons

The role of bedrock on the longitudinal profile of the Colorado River has intrigued workers for over a century. The river\u27s profile exhibits large-scale (10 to 100 km) variations in geomorphology that are qualitatively associated with changes in rock type. This study provides the first bedrock-strength data to quantitatively test the relation of bedrock-resisting to hydraulic-driving forces in Glen and Grand canyons. The intent of this study is to explore the role, if any, that bedrock has on large-scale geomorphic variations along the profile of the Colorado River. Rock-strength data collected at 84 sites along the river corridor in Glen and Grand canyons include intact-rock strength, fracture spacing , and other characteristics associated with Selby rock-mass strength (RMS). These strength data were statistically related to measurements of channel width, gradient, and calculations of unit stream power. At the canyon scale (100 km), rocks in Grand Canyon have significantly higher intact-rock strength, lower fracture spacing, and higher RMS than those in Glen Canyon. These observations correspond to the fact that Grand Canyon is steeper and narrower, and has greater mean unit stream power. Furthermore, smaller scale, reach-average values of rock strength correlate significantly to width, gradient, and unit stream power, although there are outliers related to local-scale effects such as rapids. The Colorado River runs in a narrower and steeper channel in reaches confined by resistant bedrock ( e.g., Upper Granite Gorge, RM 77-114). In contrast , reaches floored in weaker bedrock (e.g., lower Marble Canyon, river miles 37 to 58) are associated with wider channels and lower gradient. This study confirms previous research linking rock type to the geomorphology of the Colorado River. Results imply that knickzones in the profile are persistent features that reflect a dynamic equilibrium between hydraulic-driving and bedrock-resisting forces, rather than transient waves of incision due to tectonics or drainage integration. They support the hypothesis that bedrock sets the long-term, large-scale template for the Colorado River. Bedrock hypothetically acts as a direct control on the river\u27s width and gradient, particularly when the river is in contact with bedrock. Rock-strength and weathering properties of bedrock within tributary catchments, where debris flows initiate, act as an indirect control through their influence on hillslope-to-river sediment production during episodes, such as today, when the river is not on bedrock

Hanford Borehole Geologic Information System (HBGIS) Updated User’s Guide for Web-based Data Access and Export

The Hanford Borehole Geologic Information System (HBGIS) is a prototype web-based graphical user interface (GUI) for viewing and downloading borehole geologic data. The HBGIS is being developed as part of the Remediation Decision Support function of the Soil and Groundwater Remediation Project, managed by Fluor Hanford, Inc., Richland, Washington. Recent efforts have focused on improving the functionality of the HBGIS website in order to allow more efficient access and exportation of available data in HBGIS. Users will benefit from enhancements such as a dynamic browsing, user-driven forms, and multi-select options for selecting borehole geologic data for export. The need for translating borehole geologic data into electronic form within the HBGIS continues to increase, and efforts to populate the database continue at an increasing rate. These new web-based tools should help the end user quickly visualize what data are available in HBGIS, select from among these data, and download the borehole geologic data into a consistent and reproducible tabular form. This revised user’s guide supersedes the previous user’s guide (PNNL-15362) for viewing and downloading data from HBGIS. It contains an updated data dictionary for tables and fields containing borehole geologic data as well as instructions for viewing and downloading borehole geologic data

Borehole Geologic Data for the 216-Z Crib Facilities, A Status of Data Assembled through the Hanford Borehole Geologic Information System (HBGIS)

The Pacific Northwest National Laboratory (PNNL) is assembling existing borehole geologic information to aid in determining the distribution and potential movement of contaminants released to the environment and to aid selection of remedial alternatives. This information is being assembled via the Hanford Borehole Geologic Information System (HBGIS), which is being developed as part of the Characterization of Systems Project, managed by PNNL, and the Remediation Decision Support Task of the Groundwater Remediation Project, managed by Fluor Hanford, Inc. The purpose of this particular study was to assemble the existing borehole geologic data pertaining to sediments underlying the 216-Z Crib Facilities and the Plutonium Finishing Plant Closure Zone. The primary objective for Fiscal Year 2006 was to assemble the data, complete log plots, and interpret the location of major geologic contacts for each major borehole in and around the primary disposal facilities that received carbon tetrachloride. To date, 154 boreholes located within or immediately adjacent to 19 of the 216-Z crib facilities have been incorporated into HBGIS. Borehole geologic information for the remaining three Z-crib facilities is either lacking (e.g. 216-Z-13, -14, and -15), or has been identified as a lesser priority to be incorporated at a later date

Guide to using Multiple Regression in Excel (MRCX v.1.1) for Removal of River Stage Effects from Well Water Levels

A software tool was created in Fiscal Year 2010 (FY11) that enables multiple-regression correction of well water levels for river-stage effects. This task was conducted as part of the Remediation Science and Technology project of CH2MHILL Plateau Remediation Company (CHPRC). This document contains an overview of the correction methodology and a user’s manual for Multiple Regression in Excel (MRCX) v.1.1. It also contains a step-by-step tutorial that shows users how to use MRCX to correct river effects in two different wells. This report is accompanied by an enclosed CD that contains the MRCX installer application and files used in the tutorial exercises

Treatability Test Report: Characterization of Vadose Zone Carbon Tetrachloride Source Strength Using Tomographic Methods at the 216-Z-9 Site

A treatability test was conducted in 2011 at the 216-Z-9 Trench to evaluate methods for collecting characterization information that supports refined assessment of SVE performance goals based on impact to groundwater. The characterization information can also provide input to operational strategies for continued SVE operation and decisions regarding closure of the SVE system or transition to other remedies, if necessary

Methods for Assessing the Relative Amounts of Groundwater Discharge into the Columbia River and Measurement of Columbia River Gradients at the Hanford Site’s 300 Area

This report summarizes FY08 activities conducted under the Remediation and Closure Sciences Project

Investigation of Hexavalent Chromium Flux to Groundwater at the 100-C-7:1 Excavation Site

Deep excavation of soil has been conducted at the 100-C-7 and 100-C-7:1 waste sites within the 100-BC Operable Unit at the Department of Energy (DOE) Hanford Site to remove hexavalent chromium (Cr(VI)) contamination with the excavations reaching to near the water table. Soil sampling showed that Cr(VI) contamination was still present at the bottom of the 100-C-7:1 excavation. In addition, Cr(VI) concentrations in a downgradient monitoring well have shown a transient spike of increased Cr(VI) concentration following initiation of excavation. Potentially, the increased Cr(VI) concentrations in the downgradient monitoring well are due to Cr(VI) from the excavation site. However, data were needed to evaluate this possibility and to quantify the overall impact of the 100-C-7:1 excavation site on groundwater. Data collected from a network of aquifer tubes installed across the floor of the 100-C-7:1 excavation and from temporary wells installed at the bottom of the entrance ramp to the excavation were used to evaluate Cr(VI) releases into the aquifer and to estimate local-scale hydraulic properties and groundwater flow velocity

Treatability Test Plan for 300 Area Uranium Stabilization through Polyphosphate Injection

The U.S. Department of Energy has initiated a study into possible options for stabilizing uranium at the 300 Area using polyphosphate injection. As part of this effort, PNNL will perform bench- and field-scale treatability testing designed to evaluate the efficacy of using polyphosphate injections to reduced uranium concentrations in the groundwater to meet drinking water standards (30 ug/L) in situ. This technology works by forming phosphate minerals (autunite and apatite) in the aquifer that directly sequester the existing aqueous uranium in autunite minerals and precipitates apatite minerals for sorption and long term treatment of uranium migrating into the treatment zone, thus reducing current and future aqueous uranium concentrations. Polyphosphate injection was selected for testing based on technology screening as part of the 300-FF-5 Phase III Feasibility Study for treatment of uranium in the 300-Area

Investigation of the Hyporheic Zone at the 300 Area,Hanford Site

The Remediation Task of the Science and Technology (S&T) Project is intended to provide research to meet several objectives concerning the discharge of groundwater contamination into the river at the 300 Area of the Hanford Site. This report serves to meet the research objectives by developing baseline data for future evaluation of remedial technologies, evaluating the effects changing river stage on near-shore groundwater chemistry, improving estimates of contaminant flux to the river, providing estimates on the extent of contaminant discharge areas along the shoreline, and providing data to support computer models used to evaluate remedial alternatives. This report summarizes the activities conducted to date and provides an overview of data collected through July 2006. Recent geologic investigations (funded through other U. S. Department of Energy (DOE) programs) have provided a more complete geologic interpretation of the 300 Area and a characterization of the vertical extent of uranium contamination. Extrapolation of this geologic interpretation into the hyporheic zone is possible, but there is little data to provide corroboration. Penetration testing was conducted along the shoreline to develop evidence to support the extrapolation of the mapping of the geologic facies. In general, this penetration testing provided evidence supporting the extrapolation of the most recent geologic interpretation, but it also provided some higher resolution detail on the shape of the layer than constrains contaminant movement. Information on this confining layer will provide a more detailed estimate of the area of river bed that has the potential to be impacted by uranium discharge to the river from groundwater transport. Water sampling in the hyporheic zone has provided results that illustrate the degree of mixing that occurs in the hyporheic zone. Uranium concentrations measured at individual sampling locations can vary by several orders of magnitude depending on the river and near-shore aquifer elevations. It is shown in this report that the concentrations of all the measured constituents in water samples collected from the hyporheic zone vary according to the ratio of groundwater and river water in the sample. One important aspect of this is that specific conductance provides a sensitive indicator of the relative contribution of groundwater and river water in a particular sample. This is because of the large difference is specific conductance of groundwater (~400 μS/cm) and river water (~130 μS/cm). It appears that in the hyporheic zone, advection of contaminates occurs very quickly, and variations in concentrations are a function of dilution rather than any chemistry effects caused by the difference in water chemistry between groundwater and river water

Investigation of the Strontium-90 Contaminant Plume along the Shoreline of the Columbia River at the 100-N Area of the Hanford Site

Efforts are underway to remediate strontium-laden groundwater to the Columbia River at the 100-N Area of the Hanford Site. Past practices of the 100-N reactor liquid waste disposal sites has left strontium-90 sorbed onto sediments which is a continuing source of contaminant discharge to the river. The Remediation Task of the Science and Technology Project assessed the interaction of groundwater and river water at the hyporheic zone. Limited data have been obtained at this interface of contaminant concentrations, geology, groundwater chemistry, affects of river stage and other variables that may affect strontium-90 release. Efforts were also undertaken to determine the extent, both laterally and horizontally, of the strontium-90 plume along the shoreline and to potentially find an alternative constituent to monitor strontium-90 that would be more cost effective and could possibly be done under real time conditions. A baseline of strontium-90 concentrations along the shoreline was developed to help assess remediation technologies