Research and Publications - Department of Civil, Construction & Environmental Engineering

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Unique Features of the Source Loading and Management Model (SLAMM)
(Computational Hydraulics Inc., 1998-02-15) Pitt, Robert E.
A logical approach to stormwater management requires knowledge of the problems that are to be solved, the sources of the problem pollutants, and the effectiveness of stormwater management practices that can control the problem pollutants at their sources and at outfalls. SLAMM is designed to provide information on these last two aspects of this approach. SLAMM can be an important component, along with local receiving water studies, of an effective watershed management program. SLAMM was initially developed to evaluate stormwater control practices more efficiently. It soon became evident that in order to accurately evaluate the effectiveness of stormwater controls at an outfall, the sources of the pollutants or problem water flows must be known. SLAMM has evolved to include a variety of source area and end-of-pipe controls and the ability to predict the concentra-tions and loadings of many different pollutants from a large number of potential source areas. SLAMM calculates mass balances for both particulate and dis-solved pollutants and runoff flow volumes for different development character-istics and rainfalls. It was designed to give relatively simple answers (pollutant mass discharges and control measure effects for a very large variety of potential conditions). Basic types of control practices evaluated by SLAMM include detention ponds, percolation ponds, infiltration devices, porous pavements, grass swales, catchbasin cleaning, and street cleaning, plus different development alternatives. Most of these controls can be evaluated in many combinations and at many source areas as well as the outfall location. SLAMM also predicts the relative contributions of different source areas (roofs, streets, parking areas, landscaped areas, undeveloped areas, etc.) for each land use investigated. An early version of SLAMM was described by Pitt and Shawley (1982) as part of the Nationwide Urban Runoff Program study conducted in Castro Valley, CA. A detailed description of SLAMM, including examples of its use, was presented by Pitt and Voorhees (1995). The development of SLAMM began in the mid 1970s, primarily as a data reduction tool for use in early street cleaning and pollutant source identification projects sponsored by the EPA's Storm and Combined Sewer Pollution Control Program (Pitt 1979; Pitt and Bozeman 1982; Pitt 1984). Much of the information contained in SLAMM was obtained during the EPA's Nationwide Urban Runoff Program (NURP) (EPA 1983), especially the early Alameda County, California (Pitt and Shawley 1982), and the Bellevue, Washington (Pitt and Bissonnette 1984) projects. The completion of the model was made possible by the remainder of the NURP projects and additional field studies and programming support sponsored by the Ontario Ministry of the Environment (Pitt and McLean 1986), the Wisconsin Department of Natural Resources (WI DNR) (Pitt 1986), and the U.S. Environmental Protection Agency (EPA) (Pitt and Voorhees 1995). SLAMM has been commonly used as a planning level model for large watershed projects. As an example, SLAMM has been extensively used by the Wisconsin Nonpoint Source Program in its evaluation of urban areas, as described by Pitt (1986). The WI DNR uses SLAMM to identify sources of pollutants, quantify their discharges, and to evaluate alternative control practices. Its use in Wisconsin in conjunction with geographical information systems (GIS) has also been described by several authors (Thum, et al. 1990; Ventura and Kim 1993; Kim and Ventura 1993; Kim, et al. 1993; and Haubner and Joeres 1996). Another early use of SLAMM on a watershed scale was during the Toronto Area Watershed Management Strategy program (TAWMS). In this project, SLAMM was used to predict drainage area pollutant and flow discharges, SWMM was used to predict combined sewer overflow (CSO) discharges from the older sections of the city, and HSPF was used to evaluate receiving water conditions resulting from these discharges (TAWMS 1986). SLAMM is used to better understand the relationships between sources of urban runoff pollutants and runoff quality. It has been continually expanded since the late 1970s and now includes a wide variety of source area and outfall control practices. SLAMM is strongly based on field observations, with minimal reliance on theoretical processes that have not been adequately documented or confirmed in the field. Special emphasis has been placed on small storm hydrology and particulate washoff in SLAMM. Many currently available urban runoff models have their roots in drainage design where the emphasis is on very large and rare rains. In contrast, many stormwater quality problems are mostly associated with common and relatively small rains. The assumptions and simplifications that are legitimately used with drainage design models are not appropriate for water quality models. SLAMM therefore incorporates unique process descriptions to more accurately predict the sources of runoff pollutants and flows for the storms of most interest in stormwater quality analysis.
Small Storm Hydrology and Why it is Important for the Design of Stormwater Control Practices
(Computational Hydraulics Inc., 1999-02-15) Pitt, Robert E.
Different drainage design criteria and receiving water use objectives often require the examination of different types of rains for the design of urban drainage systems. These different (and often conflicting) objectives of a stormwater drainage system can be addressed by using distinct portions of the long-term rainfall record. Several historical examinations (including Heaney, et al. 1977) have also considered the need for the examination of a wide range of rain events for drainage design. However, the lack of efficient computer resources severely restricted long-term analyses in the past. Currently, computer resources are much more available and are capable of much more comprehensive investigations (Gregory and James 1996). In addition to having more efficient computational resources, it is also necessary to re-examine some of the fundamental urban hydrology modeling assumptions (Pitt 1987). Most of the urban hydrology methods currently used for drainage design have been successfully used for large "design" storms. Obviously, this approach (providing urban areas safe from excessive flooding and associated flood related damages) is the most critical objective of urban drainage. However, it is now possible (and legally required in many areas) to provide urban drainage systems that also minimize other problems associated with urban stormwater. This broader set of urban drainage objectives requires a broader approach to drainage design, and the use of hydrologic methods with different assumptions and simplifications.
Use of SLAMM in Evaluating Best Management Practices
(Computational Hydraulics Inc., 2001-02-15) Myllyoja, Rob; Baroudi, Hala; Pitt, Robert E.; Paluzzi, Jenna
Once baseline water quality data reveals that beneficial uses of a stream are no longer supported, the task of evaluating alternatives for urban watershed management can be challenging for municipal planners. While working with the municipalities within the Bear Creek watershed to develop a watershed management plan, the Clinton River Watershed Council selected the Source Loading and Management Model (SLAMM) as the main instrument. A cost-effective management tool was required to assist in evaluating the effectiveness of urban best management practices (BMPs). Evaluating the suitability of the J model was difficult because we were not aware of any previous SLAMM applications in the State of Michigan. The objective became, not only to learn about and apply the model, but also to demonstrate its applicability in similar Michigan watersheds. The Source Loading and Management Model (Pitt, 1998; Pitt and Voorhees 1995) emphasizes the use of variable quality of runoff, small storm hydrology, and particulate washoff to calculate runoff pollutant yield estimates. Unlike drainage design models, SLAMM accurately computes runoff pollutant loads and flows associated with small storm events. This is critical because most of the pollutant load is associated with the smaller, frequent runoff events. SLAMM evaluates several control practices including detention ponds, infiltration devices, porous pavements, grass swales, catchbasin cleaning, and street cleaning. These controls can be evaluated in combinations at many source areas and at the outfalls. Furthermore, SLAMM computes the relative contributions of different source areas (e.g. roofs, streets, parking areas, landscaped areas, undeveloped areas) for each land use investigated. SLAMM requires the user to define specified impervious areas and directly connected impervious areas (DCIAs) within the model's subwatershed. DCIAs include those impervious areas that flow directly to a storm sewer, drain, channel, or waterway without flowing over any pervious surfaces. SLAMM utilizes site- specific local information including stormwater conveyance system type and condition, study period duration, rainfall depth, duration, and, and detailed land use and source area descriptions. SLAMM does not require detailed drainage system information, although the newest version of the program allows interfacing with SWMM for detailed hydraulic system evaluation.
The Role of Pollution Prevention in Stormwater Management
(Computational Hydraulics Inc., 2001-02-15) Pitt, Robert E.; Lalor, Melinda
Around the nation, there is growing interest in the development and use of environmentally sensitive construction materials as a low-cost component to stormwater management. It is thought that the more appropriate selection of materials that are exposed to the environment should result in significant reductions of many toxicants in stormwater. Unfortunately, there is little data for specific alternative building materials, although much information exists targeting selected sources, especially the role of roof runoff as a significant source of zinc and other metals. Past studies have identified urban runoff as a major contributor to the degradation of many urban streams and rivers (such as Field and Turkeltaub 1981; Pitt and Bozeman, 1982; Pitt and Bissonnette, 1984; Pitt, 1995). Previous studies also found organic and metallic toxicants in urban storm-induced discharges that can contribute to receiving water degradation (such as EPA, 1983; Hoffman et al., 1984; Fram et al., 1987). Studies conducted by Pitt et al. (1995 and 2000) investigated toxic contributions to urban wet weather flow from sources such as roofs, parking areas, storage areas, streets, loading docks, vehicle service areas, and landscaped areas. Roof, vehicle service area and parking lot runoff samples were found to have the greatest organic toxicant detection frequencies and the highest levels of detected metals. Research is currently underway at the University of Alabama (UAB) to develop effective procedures for treating runoff from vehicle service areas and parking lots at its source (Clark and Pitt 1999; Pitt et al., 2000). These areas are particularly subject to spills and leaks of automotive products and exhaust emissions from frequently starting vehicles. These areas are usually isolated enough to make source area runoff treatment feasible. However, relative pollutant contributions from various roofing, wooden and paving materials themselves are also a concern which has not been adequately addressed. Due to the common use of these surfaces in our urban environments, reduction of emissions at the source is desirable, and material substitution would seem a good place to start.
Short Time-Interval Rainfall Disaggregation for Continuous Hydrologic Simulation
(Computational Hydraulics Inc., 2002-02-15) Burian, Steven J.; Durrans, S. Rocky
Traditionally design storms have been used to design and analyze urban drainage systems and hydraulic structures. Design storms can be developed with the desired temporal resolution to accommodate urban hydrology needs, but because the temporal distribution is generally arbitrary the application of complex disaggregation techniques is unwarranted. Continuous hydrologic simulation is recommended as an alternative to the traditional design storm approach for the design and analysis of hydrologic and hydraulic structures for reasons discussed in James (1994) and James and Robinson (1982). Continuous simulation models require long-term rainfall records (preferably more than 50 years) to generate the long-term statistical response of the hydrologic system required for accurate design and analysis of engineering systems and the evaluation of ecological and sustainability issues. Accurate hydrologic simulation of small urban catchments requires the use of a rainfall time series with a fine temporal resolution. Studies have shown that when the response time of a watershed is shorter than the total duration of rainfall excess, the runoff rate is observed to depend on the depth of rainfall and the intensity distribution (Ball 1994; Woolhiser and Goodrich 1988; Hjelmfelt 1981). But for fully developed hydrographs Ball (1994) found the temporal pattern of rainfall excess to have little influence over the peak discharge. Thus, for short duration storms coarse time resolution rainfall data may smooth the high rainfall intensities (especially those observed during convective storms), and runoff could be underestimated. Hernandez and Nachabe (2000) demonstrated that when Hortonian runoff is dominant, infiltration and runoff are very sensitive to time resolution. They observed finer temporal resolution rainfall to produce more runoff than coarser rainfall. In general, hydraulic analysis of drainage systems requires rainfall data in 5- to 15-minute increments to produce hydrographs that accurately predict peak flows (Nix 1994). The procurement and management of long-term rainfall records is no longer a problem for locations where records are available electronically. Today, the primary difficulties with long-term rainfall records are (1) unavailability at the desired location or (2) not being recorded at the desired temporal resolution. One solution to these problems would be to employ a synthetic rainfall generator to produce long-term rainfall fields with the desired spatial and temporal resolution. A second solution for circumstance (2) (i.e., when a long-term rainfall record exists but has too coarse temporal resolution) is to employ a temporal disaggregation technique to disaggregate the record into a finer temporal resolution. The issue then becomes the selection and application of an appropriate disaggregation method to produce a long-term rainfall record at the desired temporal resolution. This chapter compares several temporal rainfall disaggregation techniques applicable to continuous hydrologic simulation. The focus is the disaggregation of hourly rainfall records into sub-hourly increments because in North America hourly rain gauges are relatively common and the records often have sufficient lengths for use in long-term continuous simulation. The rainfall disaggregation methods included in the study were selected based on the needs of hydrologic modelers. In general, hydrologic modelers desire techniques that are conceptually intuitive, easily grasped, and sufficiently flexible that they could be applied to any locality and for any desired level of disaggregation (so they could be relatively easily standardized). Based on these criteria, the five methods selected for comparison were the uniform distribution approach (described below), the quadratic spline and quadratic interpolating polynomial approaches (described by Durrans et al. (1999)), the geometric similarity approach (the continuous-deterministic disaggregation model described by Ormsbee (1989)), and the backpropagation ANN approach (described by Burian et al. (2000)). Methods that require the estimation of numerous parameters were not included in this study. The relative performance of the five techniques for disaggregating hourly rainfall records from Alabama into 15-minute increments is reviewed below. Additional evaluation of the uniform distribution, the geometric similarity, and the ANN techniques is reported for 5-minute and 15-minute rainfall in Arkansas.
Infiltration Through Compacted Urban Soils and Effects on Biofiltration Design
(Computational Hydraulics Inc., 2003-02-15) Pitt, Robert E.; Chen, Shen-En; Clark, Shirley; Lantrip, Janice; Ong, Choo Keong; Voorhees, John
The effects of urbanization on soil structure can be extensive. Infiltration of rain water through soils can be greatly reduced, plus the benefits of infiltration and biofiltration devices can be jeopardized. This chapter is a compilation of results from several recent and on-going research projects that have examined some of these problems, plus possible solutions. Basic infiltration measurements in disturbed urban soils were conducted during the EPA-sponsored project by Pitt, et al. (1999a). The project also examined hydraulic and water quality benefits of amending these soils with organic composts. Prior EPA-funded research examined the potential of groundwater contamination by infiltrating stormwater (Pitt, et al. 1994, 1996, and 1999b). In addition to the information obtained during these research projects, numerous student projects have also been conduced to examine other aspects of urban soils, especially more detailed tests examining soil density and infiltration during lab-scale tests, and methods and techniques to recover infiltration capacity of urban soils. This chapter is a summary of this information and it is hoped that it will prove useful to both stormwater practice designers and to modelers.
Directing Sampling Based on Uncertainty Analysis
(Computational Hydraulics Inc., 2003-02-15) Graettinger, Andrew; Supriyasilp, Thanaporn; Durrans, S. Rocky; Pitt, Robert E.
Determining where and what to sample for environmental modeling of receiving waters is becoming increasingly important because the need for improved accuracy in model results conflicts with limited site sampling budgets. A quantitative approach to sampling, entitled Quantitatively Directed Exploration (QDE), provides a mathematical framework for determining the best location to sample, and what parameter should be sampled. QDE employs a first-order Taylor series expansion to estimate the uncertainty or variance in the model results. Uncertainty in input parameters is determined through data extrapolation techniques, specifically multivariate conditional probability, while model sensitivity is calculated by directly coding sensitivity derivatives into a model using ADIFOR 2.0. Combining these two matrices produces the variance in model results, which in turn is employed to direct sampling. The next sampling location is defined as the point where the variance in model results is the largest. Which input parameter to sample is determined by evaluating the contribution to the total variance produced by each input parameter. The QDE approach is demonstrated on a water quality model where non-point source loading, stream characteristics, and contaminant behavior are uncertain input parameters and concentration is the uncertain model result.
The Western U.S. Drought: How Bad Is It?
(2004-08-10) Piechota, Thomas C.; Timilsena, Janak; Tootle, Glenn; Hidalgo, Hugo; University of Alabama Tuscaloosa
Historical stream flow records and the forecast for 2004 make the current (1999–2004) drought in the southwestern United States the worst one in the past 80 years for portions of the Upper Colorado River Basin (UCRB).For the Colorado River (near Cisco, Utah), the cumulative stream flow deficit (departure from long‐term mean) for the current drought is almost 11 km8, or approximately 2 years of average stream flow Although the current drought is the most significant, based on historical stream flow records, is it the worst ever?
Coupled oceanic-atmospheric variability and U.S. streamflow
(American Geophysical Union, 2005-12-06) Tootle, GA; Piechota, TC; Singh, A; University of Wyoming; Nevada System of Higher Education (NSHE); University of Nevada Las Vegas; University of Alabama Tuscaloosa
[1] A study of the influence of interdecadal, decadal, and interannual oceanic-atmospheric influences on streamflow in the United States is presented. Unimpaired streamflow was identified for 639 stations in the United States for the period 1951 - 2002. The phases (cold/negative or warm/positive) of Pacific Ocean ( El Nino - Southern Oscillation (ENSO) and Pacific Decadal Oscillation (PDO)) and Atlantic Ocean ( Atlantic Multidecadal Oscillation (AMO) and North Atlantic Oscillation (NAO)) oceanic-atmospheric influences were identified for the year prior to the streamflow year (i.e., long lead time). Statistical significance testing of streamflow, based on the interdecadal, decadal, and interannual oceanic-atmospheric phase (warm/positive or cold/negative), was performed by applying the nonparametric rank-sum test. The results show that in addition to the well-established ENSO signal the PDO, AMO, and NAO influence streamflow variability in the United States. The warm phase of the PDO is associated with increased streamflow in the central and southwest United States, while the warm phase of the AMO is associated with reduced streamflow in these regions. The positive phase of the NAO and the cold phase of the AMO are associated with increased streamflow in the central United States. Additionally, the coupled effects of the oceanic-atmospheric influences were evaluated on the basis of the long-term phase (cold/negative or warm/ positive) of the interdecadal ( PDO and AMO) and decadal ( NAO) influences and ENSO. Streamflow regions in the United States were identified that respond to these climatic couplings. The results show that the AMO may influence La Nina impacts in the Southeast, while the NAO may influence La Nina impacts in the Midwest. By utilizing the streamflow water year and the long lead time for the oceanic-atmospheric variables, useful information can be provided to streamflow forecasters and water managers.
Oceanic-atmospheric variability and western US snowfall
(American Geophysical Union, 2006-07-08) Hunter, Thad; Tootle, Glenn; Piechota, Thomas; University of Wyoming; Nevada System of Higher Education (NSHE); University of Nevada Las Vegas; University of Alabama Tuscaloosa
A study of the influences of interdecadal and interannual oceanic-atmospheric influences on April 1 Snow-Water Equivalent (SWE) in the western U. S. is presented. SWE data was identified at 323 Natural Resources Conservation Service ( NRCS) SNOTEL (SNOwpack TELemetrysites) stations for the period of 1961 to 2004 and for 121 SNOTEL stations for the period 1941 to 2004. The phases (cold/negative or warm/positive) of Pacific Ocean [ El Nino-Southern Oscillation (ENSO) and Pacific Decadal Oscillation (PDO)] and Atlantic Ocean [ Atlantic Multidecadal Oscillation ( AMO) and North Atlantic Oscillation (NAO)] oceanic-atmospheric influences were identified for the year prior to the SWE data set. Statistical significance testing of SWE data set, based on the interdecadal and interannual oceanic-atmospheric phase (warm/positive or cold/negative) was performed by applying the nonparametric rank-sum test. The results show that in addition to the well established ENSO signal in the northwest, the PDO and AMO influence SWE variability. Additionally, the coupled effects of the oceanic-atmospheric influences were evaluated on the basis of the long-term phase (cold/negative or warm/positive) of the interdecadal ( PDO, AMO, NAO) influences and the interannual ENSO. Finally, the coupled effects of the oceanic-atmospheric influences were evaluated on the basis of the long-term phase (cold/negative or warm/positive) of the interdecadal ( AMO, PDO, NAO) phenomena. Regions in the west were identified that responded to the interdecadal/ decadal climatic coupling. By utilizing the April 1 SWE and the long lead-time approach for the oceanic-atmospheric variables, useful information can be provided to snow forecasters and water managers.
Relationships between Pacific and Atlantic ocean sea surface temperatures and US streamflow variability
(American Geophysical Union, 2006-07-19) Tootle, Glenn A.; Piechota, Thomas C.; University of Wyoming; Nevada System of Higher Education (NSHE); University of Nevada Las Vegas; University of Alabama Tuscaloosa
[ 1] An evaluation of Pacific and Atlantic Ocean sea surface temperatures (SSTs) and continental U. S. streamflow was performed to identify coupled regions of SST and continental U. S. streamflow variability. Both SSTs and streamflow displayed temporal variability when applying the singular value decomposition (SVD) statistical method. Initially, an extended temporal evaluation was performed using the entire period of record (i.e., all years from 1951 to 2002). This was followed by an interdecadal-temporal evaluation for the Pacific ( Atlantic) Ocean based on the phase of the Pacific Decadal Oscillation (PDO) ( Atlantic Multidecadal Oscillation (AMO)). Finally, an extended temporal evaluation was performed using detrended SST and streamflow data. A lead time approach was assessed in which the previous year's spring-summer season Pacific Ocean ( Atlantic Ocean) SSTs were evaluated with the current water year continental U. S. streamflow. During the cold phase of the PDO, Pacific Ocean SSTs influenced streamflow regions ( southeast, northwest, southwest, and northeast United States) most often associated with El Nino-Southern Oscillation (ENSO), while during the warm phase of the PDO, Pacific Ocean SSTs influenced non-ENSO streamflow regions ( Upper Colorado River basin and middle Atlantic United States). ENSO and the PDO were identified by the Pacific Ocean SST SVD first temporal expansion series as climatic influences for the PDO cold phase, PDO warm phase, and the all years analysis. Additionally, the phase of the AMO resulted in continental U. S. streamflow variability when evaluating Atlantic Ocean SSTs. During the cold phase of the AMO, Atlantic Ocean SSTs influenced middle Atlantic and central U. S. streamflow, while during the warm phase of the AMO, Atlantic Ocean SSTs influenced upper Mississippi River basin, peninsular Florida, and northwest U. S. streamflow. The AMO signal was identified in the Atlantic Ocean SST SVD first temporal expansion series. Applying SVD, first temporal expansions series were developed for Pacific and Atlantic Ocean SSTs and continental U. S. streamflow. The first temporal expansion series of SSTs and streamflow were strongly correlated, which could result in improved streamflow predictability.
Five Hundred Years of Hydrological Drought in the Upper Colorado River Basin
(2007-06) Timilsena, Janak; Piechota, Thomas C.; Hidalgo, Hugo; Tootle, Glenn; University of Alabama Tuscaloosa
This article evaluates drought scenarios of the Upper Colorado River basin (UCRB) considering multiple drought variables for the past 500 years and positions the current drought in terms of the magnitude and frequency. Drought characteristics were developed considering water-year data of UCRB’s streamflow, and basin-wide averages of the Palmer Hydrological Drought Index (PHDI) and the Palmer Z Index. Streamflow and drought indices were reconstructed for the last 500 years using a principal component regression model based on tree-ring data. The reconstructed streamflow showed higher variability as compared with reconstructed PHDI and reconstructed Palmer Z Index. The magnitude and severity of all droughts were obtained for the last 500 years for historical and reconstructed drought variables and ranked accordingly. The frequency of the current drought was obtained by considering two different drought frequency statistical approaches and three different methods of determining the beginning and end of the drought period (annual, 5-year moving, and ten year moving average). It was concluded that the current drought is the worst in the observed record period (1923-2004), but 6th to 14th largest in terms of magnitude and 1st to 12th considering severity in the past 500 years. Similarly, the current drought has a return period ranging from 37 to 103 years based on how the drought period was determined. It was concluded that if the 10-year moving average is used for defining the drought period, the current drought appears less severe in terms of magnitude and severity in the last 500 years compared with the results using 1- and 5-year averages.
Estimated Wind River Range (Wyoming, USA) Glacier Melt Water Contributions to Agriculture
(MDPI, 2009-10-28) Cheesbrough, Kyle; Edmunds, Jake; Tootle, Glenn; Kerr, Greg; Pochop, Larry; University of Tennessee System; University of Tennessee Knoxville; University of Wyoming; University of Alabama Tuscaloosa
In 2008, Wyoming was ranked 8th in barley production and 20th in hay production in the United States and these crops support Wyoming's $800 million cattle industry. However, with a mean elevation of 2,040 meters, much of Wyoming has a limited crop growing season (as little as 60 days) and relies on late-summer and early-fall streamflow for agricultural water supply. Wyoming is host to over 80 glaciers with the majority of these glaciers being located in the Wind River Range. These "frozen reservoirs" provide a stable source of streamflow (glacier meltwater) during this critical late-summer and early-fall growing season. Given the potential impacts of climate change (increased temperatures resulting in glacier recession), the quantification of glacier meltwater during the late-summer and early-fall growing seasons is needed. Glacier area changes in the Wind River Range were estimated for 42 glaciers using Landsat data from 1985 to 2005. The total surface area of the 42 glaciers was calculated to be 41.2 +/- 11.7 km(2) in 1985 and 30.8 +/- 8.2 km(2) in 2005, an average decrease of 25% over the 21 year period. Small glaciers experienced noticeably more area reduction than large glaciers. Of the 42 glaciers analyzed, 17 had an area of greater than 0.5 km(2) in 1985, while 25 were less than 0.5 km(2) in 1985. The glaciers with a surface area less than 0.5 km(2) experienced an average surface area loss (fraction of 1985 surface area) of 43%, while the larger glaciers (greater than 0.5 km(2)) experienced an average surface area loss of 22%. Applying area-volume scaling relationships for glaciers, volume loss was estimated to be 409 x 106 m(3) over the 21 year period, which results in an estimated 4% to 10% contribution to warm season (July-October) streamflow.
The 2009-2010 El Niño: Hydrologic Relief to U.S. Regions
(2009-12-15) Tootle, G. A.; Piechota, T. C.; Aziz, O.; Miller, W. P.; Lakshmi, V.; Dracup, J. A.; Jerla, C.; University of Alabama Tuscaloosa
Current forecasts by the U.S. National Oceanic and Atmospheric Administration (NOAA) are that the Pacific Ocean will experience El Niño conditions in late 2009 and into 2010. These forecasts are similar to past El Niño events in 1972–1973, 1982–1983, 1986–1987, and 2002–2003.Evaluating the hydrologic conditions for these past El Niño events reveals that during these times, surface water supply conditions improved in many parts of the United States, including the Southeast, Midwest, and Southwest. At the same time, the Pacific Northwest and other specific regions of the United States experienced below‐average water supply conditions. This is consistent with the long‐established linkages between oceanic‐atmospheric phenomena, El Niño, and streamflow [e.g., Kahya and Dracup, 1993; Tootle et al., 2005].
High-Rate Stormwater Treatment with Up-Flow Filtration
(Computational Hydraulics Inc., 2010-02-15) Togawa, Noboru; Pitt, Robert
The objective of this research is to examine the removal capacities of a high-rate stormwater filtration device, in part developed by engineers at the University of Alabama through a small business innovative re-search grant from the U.S. Environmental Protection Agency. The Up-Flo Filter is an efficient high-rate stormwater filtration technology de-signed for the removal of trash, sediments, nutrients, metals and hydrocarbons from stormwater runoff. Compared with traditional downflow filtration treatment, upflow filtration can minimize clogging problems while providing a high rate of flow. The Up-Flo filter was de-veloped to remove a broad range of stormwater pollutants, especially those associated with particulates. The high flow rate capacities of the Up-Flo filter are accomplished through controlled fluidization of the filtration media, while still capturing very small particulates, that is lo-cated in a flexible, but constraining, media container. The Up-Flo filter also drains down between rain events which minimizes anaerobic con-ditions in the media and which also partially flushes captured particulates from the media to the storage sump, decreasing clogging and increasing run times between maintenance. Gross floatables are captured through the use of an angled screen before the media and a hood on the overflow siphon, while the sump captures bed load par-ticulates.
Identification of Pacific Ocean sea surface temperature influences of Upper Colorado River Basin snowpack
(American Geophysical Union, 2010-07-27) Aziz, Oubeidillah A.; Tootle, Glenn A.; Gray, Stephen T.; Piechota, Thomas C.; University of Tennessee System; University of Tennessee Knoxville; University of Wyoming; Nevada System of Higher Education (NSHE); University of Nevada Las Vegas; University of Alabama Tuscaloosa
Given the importance of Upper Colorado River Basin (UCRB) snowpack as the primary driver of streamflow (water supply) for the southwestern United States, the identification of Pacific Ocean climatic drivers (e. g., sea surface temperature (SST) variability) may prove valuable in long-lead-time forecasting of snowpack in this critical region. Previous research efforts have identified El Nino-Southern Oscillation (ENSO) and Pacific Decadel Oscillation (PDO) as the main drivers for western U. S. snowpack, but these drivers have limited influence on regional (Utah and Colorado) UCRB snowpack. The current research applies for the first time the Singular Value Decomposition (SVD) statistical method to Pacific Ocean SSTs and continental U. S. snowpack to identify the primary Pacific Ocean climatic driver of UCRB snowpack. The use of SSTs eliminates any "bias" as to specific climate signals. The second mode of SVD identified a UCRB snowpack region (Colorado and Utah) and a corresponding Pacific Ocean SST region. A "non-ENSO/non-PDO" Pacific Ocean SST region between 34 degrees N-24 degrees S and 150 degrees E-160 degrees W was identified as being the primary driver of UCRB snowpack. To confirm the UCRB snowpack results, data from 13 unimpaired (or naturalized) streamflow gages in Colorado and Utah were used to evaluate and support the snowpack findings. Finally, a new and beneficial data set (western U.S. 1 March, 1 April, and 1 May snow water equivalent) was developed, which may be used in future research efforts.
Greening China Naturally
(Springer, 2011) Cao, Shixiong; Sun, Ge; Zhang, Zhiqiang; Chen, Liding; Feng, Qi; Fu, Bojie; McNulty, Steve; Shankman, David; Tang, Jianwu; Wang, Yanhui; Wei, Xiaohua; United States Department of Agriculture (USDA); United States Forest Service; Beijing Forestry University; Chinese Academy of Sciences; Research Center for Eco-Environmental Sciences (RCEES); Cold & Arid Regions Environmental & Engineering Research Institute, CAS; University of Alabama Tuscaloosa; Marine Biological Laboratory - Woods Hole; Chinese Academy of Forestry; Research Institute of Forest Ecology, Environment and Protection, CAF; University of British Columbia; University of British Columbia Okanagan
China leads the world in afforestation, and is one of the few countries whose forested area is increasing. However, this massive "greening" effort has been less effective than expected; afforestation has sometimes produced unintended environmental, ecological, and socioeconomic consequences, and has failed to achieve the desired ecological benefits. Where afforestation has succeeded, the approach was tailored to local environmental conditions. Using the right plant species or species composition for the site and considering alternatives such as grassland restoration have been important success factors. To expand this success, government policy should shift from a forest-based approach to a results-based approach. In addition, long-term monitoring must be implemented to provide the data needed to develop a cost-effective, scientifically informed restoration policy.
A Web-Based Geotechnical GIS
(Wiley, 2011-10-05) Graettinger, Andrew J.; Ryals, Zachary T.; Smith, Randy K.
A web-based Geotechnical Geographic Information System (GeoGIS) was developed and tested for the Alabama Departmentof Transportation. This web-based system stores geotechnical information about transportation projects, such as subsurface data,construction drawings, and design information. Typically, this information is in a report or plan sheet format, but raw geotechnicaldata can also be accommodated in the GeoGIS. The goal of this system is to provide easy access and storage for all geotechnicaland subsurface structural information from across a state. Access through a secure web interface allows for keyword searches andinteractive map selection. The web-based GeoGIS has four geotechnical layers (project, bridge, foundation, and soil boring) thatcan be displayed on a road map, aerial photos, or USGS 7.5 minute quadrangles. For testing purposes the GeoGIS was populatedwith multiple document types, formats, and sizes. In all cases, the system performed above expectations.
Snowpack Reconstructions Incorporating Climate in the Upper Green River Basin (Wyoming)
(2012) Anderson, Sallyrose; Moser, Cody L.; Tootle, Glenn A.; Grissino-Mayer, Henri D.; Timilsena, Janak; Piechota, Thomas; University of Alabama Tuscaloosa
The Green River is the largest tributary of the Colorado River. Given that snowpack is the primary driver of streamflow, information on the long-term regional snowpack (regionalized April 1 Snow Water Equivalent (SWE)) variability would provide useful information for water managers and planners. Previous research efforts were unable to develop skillful SWE reconstructions using tree-ring chronologies in the Upper Green River Basin (UGRB) of Wyoming because of limited tree-ring chronologies in the area. The current research uses Principal Components Analysis to regionalize April 1 snowpack data in the UGRB. Recent research efforts developed six new tree-ring chronologies in and adjacent to the UGRB. These new chronologies, along with 38 existing chronologies, were correlated with the regionalized SWE data. Chronologies positively correlated at a 95% confidence level or higher were retained. Stepwise linear regressions were performed and a reconstruction of UGRB regional April 1 SWE was achieved (R2 = 0.21). Climate signals (Pacific Decadal Oscillation (PDO) and Southern Oscillation Index (SOI)) were introduced to the predictor variables and an additional regression was performed. Inclusion of the SOI resulted in a statistically skillful reconstruction (R2 = 0.58). Temporal drought periods for SWE and for streamflow were examined for the UGRB and a direct relationship was observed.
Polycyclic Aromatic Hydrocarbons in Urban Stream Sediments
(2012) Bathi, Jejal Reddy; Pitt, Robert E.; Clark, Shirley E.; University of Alabama Tuscaloosa
Polycyclic aromatic hydrocarbons (PAHs) are persistent organic pollutants of high environmental concern with known carcinogenic activity. Although literature documents PAH fate in urban runoff, little is known about their distribution on sediment sizes, which is essential for determining their treatability and fate in receiving waters. This paper has quantified the concentrations of selected PAHs in urban creek sediments and examined possible relationships between sediment PAH content and sediment characteristics, such as particle size, volatile organic content (VOC), and sediment chemical oxygen demand (SCOD). SCOD, VOC, and PAH concentrations of sediments showed a bimodal distribution by particle size. The large diameter sediments had the highest VOC and also had the highest PAH concentrations. The spatial variation of PAH content by sediment sizes also was statistically significant; however, the mass of the PAH material was significantly affected by the relative abundance of the different particle size classes in the sediment mixtures.

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