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W.M. Alley

Publications and source records attributed to W.M. Alley.

9 recordsLinked to original sources
USGS2011

Towards sustainable groundwater use: Setting long-term goals, backcasting, and managing adaptively

The sustainability of crucial earth resources, such as groundwater, is a critical issue. We consider groundwater sustainability a value‐driven process of intra‐ and intergenerational equity that balances the environment, society, and economy. Synthesizing hydrogeological science and current sustainability concepts, we emphasize three sustainability approaches: setting multigenerational sustainability goals, backcasting, and managing adaptively. As most aquifer problems are long‐term problems, we propose that multigenerational goals (50 to 100 years) for water quantity and quality that acknowledge the connections between groundwater, surface water, and ecosystems be set for many aquifers. The goals should be set by a watershed‐ or aquifer‐based community in an inclusive and participatory manner. Policies for shorter time horizons should be developed by backcasting, and measures implemented through adaptive management to achieve the long‐term goals. Two case histories illustrate the importance and complexity of a multigenerational perspective and adaptive management. These approaches could transform aquifer depletion and contamination to more sustainable groundwater use, providing groundwater for current and future generations while protecting ecological integrity and resilience.

Ground Water↗
USGS1989

Well installation and documentation, and ground-water sampling protocols for the pilot National Water-Quality Assessment Program

Several pilot projects are being conducted as part of the National Water Quality Assessment (NAWQA) Program. The purpose of the pilot program is to test and refine concepts for a proposed full-scale program. Three of the pilot projects are specifically designed to assess groundwater. The purpose of this report is to describe the criteria that are being used in the NAWQA pilot projects for selecting and documenting wells, installing new wells, and sampling wells for different water quality constituents. Guidelines are presented for the selection of wells for sampling. Information needed to accurately document each well includes site characteristics related to the location of the well, land use near the well, and important well construction features. These guidelines ensure the consistency of the information collected and will provide comparable data for interpretive purposes. Guidelines for the installation of wells are presented and include procedures that need to be followed for preparations prior to drilling, the selection of the drilling technique and casing type, the grouting procedure, and the well-development technique. A major component of the protocols is related to water quality sampling. Tasks are identified that need to be completed prior to visiting the site for sampling. Guidelines are presented for purging the well prior t sampling, both in terms of the volume of water pumped and the chemical stability of field parameters. Guidelines are presented concerning sampler selection as related to both inorganic and organic constituents. Documentation needed to describe the measurements and observations related to sampling each well and treating and preserving the samples are also presented. Procedures are presented for the storage and shipping of water samples, equipment cleaning, and quality assurance. Quality assurance guidelines include the description of the general distribution of the various quality assurance samples (blanks, spikes, duplicates, and reference samples) that will be used in the pilot program. (Lantz-PTT)

Open-File Report↗
USGS1988

A summary of the U.S. Geological Survey National Water-Quality Assessment program

Beginning in 1986, the Congress appropriated funds for the U.S. Geological Survey to test and refine concepts for a National Water Quality Assessment Program. At present, the program is in a pilot phase with field studies occurring in seven areas around the Nation. In 1990, a committee of the National Academy of Sciences will complete an evaluation of the design and potential utility of the program. A decision about moving to full-scale implementation will be made upon completion of this evaluation. The program is intended to address a wide range of national water quality issues that include chemical contamination, acidification, eutrophication, salinity, sedimentation, and sanitary quality. The goals of the program are to: (1) provide nationally consistent descriptions of current water quality conditions for a large part of the Nation 's water resources; (2) define long-term trends (or lack of trends) in water quality; and (3) identify and describe the relations of both current conditions and trends in water quality to natural and human factors. This information will be provided to water managers, policy makers, and the public to provide an improved scientific basis for evaluating the effectiveness of water quality management programs and for predicting the likely effects of contemplated changes in land- and water-management practices. (USGS)

Open-File Report↗
USGS1986

Groundwater model of the Blue River basin, Nebraska-Twenty years later

Groundwater flow models have become almost a routine tool of the practicing hydrologist. Yet, surprisingly little attention has been given to true verification analysis of studies using these models. This paper examines predictions for 1982 of water-level declines and streamflow depletions that were made in 1965 using an electric analog groundwater model of the Blue River basin in southeastern Nebraska. Analysis of the model's predictions suggests that the analog model used too low an estimate of net groundwater withdrawals, yet overestimated water-level declines. The model predicted that almost all of the net groundwater pumpage would come from storage in the Pleistocene aquifer within the Blue River basin. It appears likely that the model underestimated the contributions of other sources of water to the pumpage, and that the aquifer storage coefficients used in the model were too low. There is some evidence that groundwater pumpage has had a greater than predicted effect on streamflow. Considerable uncertainty about the basic conceptualization of the hydrology of the Blue River basin greatly limits the reliability of groundwater models developed for the basin. The paper concludes with general perspectives on groundwater modeling gained from this post-audit analysis.

Nebraska↗
USGS1984

The Palmer Drought Severity Index: limitations and assumptions.

The structure of the Palmer Drought Severity Index (PDSI), which is perhaps the most widely used regional index of drought, is examined. The PDSI addresses two of the most elusive properties of droughts: their intensity and their beginning and ending times. Under certain conditions, the PDSI values are very sensitive to the criteria for ending an 'established' drought and precipitation during a month can have a very large effect on the PDSI values for several previous months. -from Author

Journal of Climate and Applied Meteorology↗
USGS1983

Mixed-station extension of monthly streamflow records.

Monthly streamflow records at a site are sometimes extended by exploiting interstation correlation of streamflow, often through simple linear regression with a base station having a long-term record. An approach is presented which selects a base station from among several in a region for filling in missing data. It differs from traditional approaches in that different stations can be selected as the base station to fill in different values. Application of the approach demonstrated large reductions in the streamflow prediction error for two sites in Colorado.-from ASCE Publications Information

Journal of Hydraulic Engineering↗
USGS1982

Distributed routing rainfall-runoff model; version II

A computer program of a watershed model for routing storm runoff through a branched system of pipes and (or) natural channels using rainfall as input is described. The model provides detailed simulation of storm-runoff periods selected by the user and a daily soil-moisture accounting between storms. A drainage basin is represented as a set of overland-flow, channel, and reservoir seqments which ,jointly describe the drainage features of the basin. Kinematic wave theory is used for routing flows over contributing overland-flow areas and through the channel network. A set of model segments can be arranged into a network that will represent many complex drainage basins. The model is intended primarily for application to urban watersheds, but may have limited applications to rural watersheds.

Open-File Report↗
USGS1982

Multi-event urban runoff quality model

A computer model is presented for simulating the quality of surface runoff from urban watersheds. The model can simulate impervious area, pervious area, and precipitation contributions to runoff quality as well as the effects of street sweeping and (or) detention storage. Within-storm variations of runoff quality are simulated for user-specified storm-runoff periods. Between these storms, a daily accounting of the accumulation and washoff of water-quality constituents on effective impervious areas is maintained. The time step of the within-storm simulations can range from 1 to 60 minutes. The model can be operated as a lumped-parameter model or as a distributed-parameter model. As a lumped-parameter model, no spatial variations in model parameters are accounted for, and input to the model requires flow hydrographs only at the outlet of the watershed. The outlet hydrographs can be either observed or simulated. As a distributed-parameter model, the model requires flow hydrographs at many points in the watershed, as defined by basin segmentation. These hydrographs will normally be simulated by the Distributed Routing Rainfall-Runoff Model. This report includes a presentation of the theory and limitations of the model, as well as a program listing, instructions for running the program, and example simulations.

Open-File Report↗