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Georgia Water Resources Institute

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https://hdl.handle.net/1853/70796

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School of Civil and Environmental Engineering

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Stream Flow Changes Associated With Water Use and Climatic Variation in the Lower Flint River Basin, Southwest Georgia

(Georgia Institute of Technology, 2007-03) Golladay, Stephen W. ; Hicks, David W. ; Muenz, Tara K.

In the 1970’s agricultural water use expanded rapidly in the lower Flint River Basin resulting from the introduction of center pivot irrigation technology. The rapid expansion has raised concerns about impacts on regional stream flows essential to support aquatic fauna. Using long-term stream gage records from the USGS and climate data, we analyzed trends in stream flow in two major sub-watersheds and regional patterns of rainfall from 1940 through 2004. We observed no change in annual rainfall but seasonality changed with winters being slightly wetter. Minimum flows showed substantial declines since the development of irrigation. We attribute altered stream flows to increased regional water demand however; the demand for water is also exacerbated by long-term variations in climate and rainfall distribution.
Current Conditions of Historical Mussel Habitat in the Flint River Basin, Georgia

(Georgia Institute of Technology, 2007-03) Muenz, Tara K. ; Opsahl, Stephen P. ; Golladay, Stephen W.

Streams of the Flint River Basin (FRB) remain as viable habitat for many freshwater species and harbor some of the most diverse mussel assemblages in the Southeast. However, land use changes, hydrologic alterations, and declines in native fish species have adversely affected mussel diversity and abundance throughout the region. Protection of rare and sensitive mussels requires the development of timely conservation strategies, supported by knowledge of current riparian and instream habitat conditions that impact their survival and recovery. We examined habitat conditions and selected water quality parameters at 81 stream sites that have historically supported populations of freshwater mussel species in the Basin. Higher nutrient, sediment, and bacterial concentrations were observed in the upper portion (Piedmont) of the Basin, which is characterized by higher gradient streams and percentages of urban land use. Sites in the lower section of the Basin (Fall Line Hills and Coastal Plain) maintained better quality riparian habitat including a larger buffer zone width, greater bank stability, and more vegetative cover. Overall, mussel habitat quality appeared good throughout the Basin. Physicochemical parameters and riparian habitat quality were influenced both by regional geologic differences and patterns of human activity.
Using Adopt-A-Stream in the coastal plain: a look at the macroinvertebrate index

(Georgia Institute of Technology, 2005-04) Muenz, Tara K. ; Golladay, Stephen W. ; Vellidis, George

As major threats to Georgia’s waterways continue, volunteer-based monitoring groups such as Georgia Adopt-A-Stream (GA AAS) have become a vital source of information on aquatic ecological condition. Biological monitoring is an important component of the program, with macroinvertebrates serving as the primary tool for assessing water quality. We evaluated the validity and applicability of the GA AAS macroinvertebrate index on three impacted and two reference streams within an agricultural landscape in the Coastal Plain region of southwest Georgia. We compared these findings to a concurrent study that examined the condition of streams impacted by grazing livestock, through water quality, physical and vegetative parameters as well as macroinvertebrate metrics. The GA AAS index for macroinvertebrates proved to be effective in separating sites with different impacts, showing similar results as most invertebrate indices, and appears to be a valid tool to assess the ecological condition of Coastal Plain streams.
Distribution of unionid mussels in tributaries of the Lower Flint River, Southwestern Georgia: an examination of current and historical trends

(Georgia Institute of Technology, 2005-04) Chastain, Charlotte A. ; Golladay, Stephen W. ; Muenz, Tara K.

The historically diverse assemblage of freshwater mussels in the Flint River Basin (FRB) has shown declines in abundance and distribution. The mid-reaches of the major tributaries of the Flint River contained one of the richest assemblages of mussels in the southeastern Coastal Plain. Declines in mussel assemblages were accelerated by the recent drought that occurred during 1999-2001. Following the drought, we surveyed mussel populations at selected sites in the major tributaries of the Flint River to determine if declines in abundance and distribution were continuing. Many populations of common, rare, and endangered species were stable in their distribution but exhibited declines in numbers. One survey site in particular, on Spring Creek, contains a rich assemblage of mussels unique to this basin, and surveys from this site also suggest population declines. Possible explanations for declines include poor water quality, loss or degradation of instream habitat, competition from the exotic Asiatic clam, and inadequate instream flows.
Comparison of bioassessment methods of ecological condition using aquatic macroinvertebrate assemblages in Southwest Georgia headwater streams

(Georgia Institute of Technology, 2005-04) Winn, Rebecca T. ; Crisman, Thomas L. ; Golladay, Stephen W.

Despite their importance, most biomonitoring programs ignore headwater streams, and focus their usually limited resources on larger streams. This study compared aquatic macroinvertebrate assemblages using Georgia Department of Natural Resources’ (DNR) Georgia Bioassessment Protocol (GBP) and Georgia Adopt-A-Stream’s (AAS) assessment protocol for four relatively undisturbed headwater streams. The rating of ecological condition/water quality of study streams by the GBP and AAS index differed slightly with a greater percentage of samples rated excellent or poor by the AAS index when compared to GBP results. The AAS index detected differences between sampling periods and streams that agreed with commonly used metrics such as Ephemeroptera, Plecoptera, and Trichoptera (EPT) taxa. Study results do not suggest that one assessment method is better at describing streams than the other, but they do suggest that the coarser taxonomic resolution employed by the AAS index is adequate to conduct assessments.
Wood debris recruitment from differing riparian landforms in a gulf coastal plain stream: the role of floods

(Georgia Institute of Technology, 2005-04) Golladay, Stephen W. ; Battle, Juliann

Wood recruitment dynamics in Coastal Plain streams are complex. Recruitment rates are dependent on stream valley morphology, forest composition, and flow diversity. Infrequent high flows are critical in the maintenance of the instream debris pool. Following extensive flooding in 1994, surveys of downed trees were made across replicated riparian landforms (floodplains, terraces, and sand ridges) in a Gulf Coastal Plain 5th order stream. Annually, the fate of these trees was determined and newly recruited trees were noted. Generally, tree recruitment was greatest in years with substantial floods (1994 and 1998). For each riparian landform type, tree mortality was correlated with the maximum daily flow during the period preceding annual debris surveys.
Hydrologic and sediment transport response to forestry; southwest Georgia headwater streams

(Georgia Institute of Technology, 2005-04) Summer, W. B. ; Jackson, C. Rhett ; Jones, D. ; Golladay, Stephen W. ; Miwa, M.

Properly established streamside management zones (SMZs) reduce potential impacts of timber harvesting on stream sediment fluxes. However, effects of partial harvesting within SMZs on water quality are not well documented. The objectives of this study are to examine the effects of forestry activities on hydrology and sediment export in undisturbed first-order streams as part of a long-term paired watershed study. The study design includes two reference (no harvest) and two treatment watersheds (all are between 26 – 48 hectares in size). The entire treatment watersheds were harvested except for SMZs, which were divided into upper and lower sections. The upper sections had an intact SMZ, while the lower sections were thinned according to Georgia best management practices (BMP) guidelines. Flow and sediment concentrations were monitored at the outlet of each treatment and reference watershed for two years prior to and one year following harvest. Though peak flow rates have not significantly increased in treatment watersheds as a result of harvest, cumulative flows have doubled. Observations of variable source areas indicate water tables have risen in treatment watersheds.
Mussel Conservation in the Chickasawhatchee and Elmodel Wildlife Management Areas: Methods for a Relocation Study

(Georgia Institute of Technology, 2003-04) Battle, Juliann ; Golladay, Stephen W. ; Bambarger, A. Raynie

Southwest Georgia has among the richest mussel assemblages in the world. The Chickasawhatchee Wildlife Management Area (WMA), location of the second largest swamp in Georgia, and the Elmodel WMA have recently been placed into permanent conservation status (+15,000 acres) providing an opportunity for the management of mussels. In 2001, 16 locations within the WMAs were surveyed for mussels using visual and tactile methods. Nine species were found with one being very rare (Alasmidonta triangulata) and another federally endangered (Lampsilis subangulata). Mussel densities were much lower than those found in nearby streams, which may be due to prior land use and historical droughts. During the spring of 2003, we plan to relocate three mussel species (Elliptio complanata, E. crassidens, Villosa vibex) that serve as surrogates for endangered species. Their survivorship will be observed for two years; in addition, water quality and hydrology will be monitored. We hope that with the development of relocation methods and identification of suitable habitat, populations of endangered species can eventually be established within the WMAs.
The Effects of the 2000 Drought on Freshwater Mussels in the Lower Flint River Basin

(Georgia Institute of Technology, 2003-04) Golladay, Stephen W. ; Gagnon, Paula ; Kearns, Margaret ; Battle, Juliann ; Hicks, David W.

A drought during the summer of 2000 caused record low flows in the lower Flint River Basin (FRB) and many perennial streams dried or became intermittent. Pre-drought surveys conducted in 1999 allowed an assessment of the impact of the drought on mussel assemblages. During 2001, 21 stream reaches which had abundant or diverse mussel assemblages were resurveyed. Where possible, study sites were classified as flowing or non-flowing during the drought. Mussel abundance at sites classified as non-flowing showed significant declines (median value 80% decrease) compared to flowing sites (median value 5% increase). Generally, greatest declines in mussel abundance occurred in the mid-reaches of the major tributaries of the lower Flint River. Declines in mussel populations appear to be associated with unusual climatic conditions and increasing demand on the area streams and the regional aquifer system for irrigation water supply.
Stream macroinvertebrates and amphibians as indicators of ecosystem stress: a case study from the Coastal Plain, GA

(Georgia Institute of Technology, 2003-04) Muenz, Tara K. ; Golladay, Stephen W. ; Vellidis, George ; Smith, Lora L.

Conservation buffers are one strategy adopted by various federal and state agencies to aid in the reduction of agricultural impacts on surface and ground water systems. A diversified row crop and beef cattle operation located on a tributary of the Lower Chattahoochee River in Early County, southwest Georgia was the selected site for this study. A suite of indicators were chosen to evaluate the impact of agriculture on three unfenced and two fenced stream sites. Preliminary results provide no discernible differences in herpetofaunal captures between sites, except for larval salamanders captured within bimonthly invertebrate samples, which were more abundant at fenced sites. Percentages of EPT, Coleoptera and Crustacea were also higher at fenced sites, which also showed lower levels of nitrate-N, suspended solids, and fecal coliforms. Exclusion sites, which had been fenced out three years prior to this study, suggest some recovery from cattle impacts.