APPENDIX F

 

AN ASSESSMENT OF THE BIOLOGICAL INTEGRITY

OF THE WICHITA RIVER BASIN

USING MACROINVERTEBRATES

 

January 1997

 

BASIN SUMMARY REPORT

FOR THE

RED RIVER BASIN

September 1999

 

 

 

1.0       Abstract

 

This study assessed the biological integrity, using a modified Rapid Bioassessment (RBA) Protocol II of several streams in the Wichita River Basin, by analyzing the collections of macroinvertebrate populations.  The assessment consisted of an RBA score, habitat assessment score, and a knowledge of water quality (i.e. high total dissolved solids and turbidity).  Three of the sampling sites exhibited moderate impairment, while the other two exhibited non-impairment.  The sampling sites located on the North Fork and the South Fork of the Wichita River exhibited the lowest RBA scores, which is attributed to the combination of harsh water quality conditions and the lack of suitable habitat for colonization.  Overall, biological integrity appeared to be most affected by habitat availability and suitability.  Water quality (i.e. high total dissolved solids and turbidity) appeared to affect the biological integrity of the sampling sites throughout the basin.

 

2.0       Introduction

 

A study utilizing macroinvertebrate communities was performed in the Wichita River Basin between September 27, 1996 ) October 4, 1996.  The goals of this study were to assess the water quality in the basin and secondly to supply valuable information concerning the macroinvertebrate taxa present in the Wichita River Basin, thus providing data for future comparisons in performing trend analysis.  There has been minimal biological sampling performed within the Wichita River Basin (as is the case throughout the Red River Basin), therefore through the Clean Rivers Program, the Authority plans to alleviate this deficiency for both macroinvertebrates and nekton.

 

A modified Rapid Bioassessment Protocol II was used in this study, which used seven metrics to attempt to quantify biological health for streams that were sampled (Plafkin et al., 1989 and Barbour et al., 1992).  These biological integrity scores are beneficial in that they integrate water quality over a relatively long period of time (as compared to taking a grab sample for water chemistry analysis).  Also, trends in biological health can be determined if these RBA's are performed periodically.

 

Descriptions of the sampling sites are listed below in Table 1 and a map showing these sites can be seen in Figure 1.

 

Table 1

Description of Five Sampling Sites in the Bioassessment Study

 

 

 

3.0       Methods and Materials

 

3.1Rapid Bioassessment Methodology

 

Pollution tolerance values for macroinvertebrates were assigned based on values established by the Texas Natural Resource Conservation Commission (handout given by Bill Harrison), the EPA (Plafkin, 1989), or from Lenat, 1993.  Functional feeding groups for macroinvertebrate families were assigned based on classifications obtained from Merritt and Cummins (1996).  Several insect families have been assigned multiple functional feeding group classifications by Merritt and Cummins (1996).  In order to clarify these classifications, organisms were further identified to genus, and when possible, to species (Merritt, R.W., 1996, Parrish R.K., 1975, and Thorp, J.H., 1991).  The data thus recorded was used to score seven metrics for a slightly modified Rapid Bioassessment Protocol II (RBP II).

 

Figure 1

 

 

The following metrics were scored in the study:

 

Structure Metrics:

 

1.   Taxa Richness = total number of taxa collected at the site.

 

2    EPT Index = number of genera belonging to the Orders Ephemeroptera, Plecoptera and Trichoptera which were collected.

 

3.   Community Loss Index = (taxa richness at the reference site ) taxa common to reference and sampling sites)/taxa richness at the sampling site.

 

Community Balance Metrics:

 

4.   Family Biotic Index (modified) = E(x_i t_i)/n, where:

 

x_i   =          number of individuals within a taxa,

t_i    =          tolerance value for the taxa,

n    =          total number of organisms in the sample.

 

5.   Percent Contribution of Dominant Family = percent contribution of the dominant taxa to the total number of organisms collected.

 

Functional Feeding Group Metrics:

 

6.   Ratio of Scrapers/Filtering Collectors = number of scrapers/(number of scrapers + number of filtering collectors).

 

7.   Quantitative Similarity Index = (Functional Feeding Groups or FFGs) ) compares two communities in terms of presence or absence of FFGs, also taking relative abundance into account.

 

Each metric value obtained was given a Biological Condition Score of 0, 3, or 6, based on its percent comparison to the metric value obtained from reference station data.  Scoring criteria for the Percent Contribution of Dominant Family was expressed as the actual percent contribution, not percent comparability to the reference station.  The Community Loss Index and Quantitative Similarity Index (FFGs) were not given a percent comparability to the reference station, because a comparison to the reference station is incorporated into these indices.  The metric scores for each sampling site were totaled, and were compared to the total metric score for the reference site to obtain the Percent Comparability to Reference Site value.

The reference site in this study was Buffalo Creek, due to its superior biological and physical health.  It should be noted that Buffalo Creek is not an optimal reference site, due to the influence of anthropogenic activities (i.e. WWTP effluent discharge).  However, there are no sites in this region that are not affected substantially by anthropogenic activity.

 

A habitat assessment matrix was completed for each sampling site using forms taken from Plafkin et al., 1989.  The matrices were evaluated to determine percent comparability of habitat between the sampling sites and the reference sites.  The percent comparability was used to judge the potential for each sampling site to support a similar level of biological health compared to its reference site.

 

3.2Sampling Methodology

 

The sampling methodology for this study consisted of using a D-framed kicknet to sweep woody habitat, vegetation, and perform kick samples within riffles.  Due to inconsistencies in the amounts and types of habitat between the sampling sites, a perfectly consistent sampling method could not be implemented.  Therefore, the sampling method consisted of performing five minute sweeps, partitioning the five minutes between the most suitable macroinvertebrate habitats.  The different habitats are sampled approximately the same percentage as they are present.  For example, if the habitat consisted of approximately 60% bank woody habitat and 40% channel woody habitat, then the bank woody habitat would be sampled for three minutes and the channel woody habitat would be sampled for two minutes.  If less than 100 macroinvertebrates are collected after the five minutes, then another five minutes of sampling are conducted.  Lastly, a submerged log was removed from each stream and the macroinvertebrates were collected.  This is also performed for approximately five minutes, in an attempt to represent the shredder population, with consistent methodology.  The following paragraphs describe the exact methodology for each site in the study.

 

South Fork Wichita River at Waggoner Ranch Road ) 10/4/96

 

Two five minute sweeps were taken in approximately 40% bank woody habitat, 25% in overhanging bank vegetation and 35% channel woody habitat.  Riffles were sampled below the bridge and no invertebrates were found due to deposition/lack of interstitial space.  Abundance of invertebrates at this site was quite low.  A submerged log was picked for five minutes and had no invertebrates apparently due to siltation on the log.

North Fork Wichita River at Highway 267 ) 10/4/96

 

Three minutes of kick sampling was performed in riffle habitat, one minute of sweeping was performed in bank woody habitat and one minute of sweeping was performed in channel woody habitat.  Invertebrates from the riffle habitat were kept separate from the invertebrates collected in woody habitat.  A submerged log was picked for five minutes and had no invertebrates, apparently due to siltation on the log.

 

Beaver Creek at FM 2326 ) 10/3/96

 

One five minute sweep was performed, approximately three and one-half minutes of the sample time within channel woody habitat and one and one-half minutes in bank woody habitat.  A submerged log was picked for five minutes.

 

Buffalo Creek at FM 1814 ) 9/27/96

 

One five minute sweep was performed, with approximately 10% of the time in riffle habitat, 50% in bank woody habitat, 20% channel woody habitat, and 20% submerged vegetation (grass) at the edge of the stream.  A submerged log was picked for five minutes.

 

Wichita River at Highway 25 ) 9/27/96

 

Two five minute sweeps were performed with approximately 50% of the time in overhanging bank vegetation, 20% woody habitat, and 30% in bank woody habitat.  A submerged log was picked for five minutes.

 

4.0       Results

 

The results in this study include the actual metric scores for each site, as well as the overall RBA score obtained, which are displayed in Table 2.  Second, a listing of the invertebrates collected and where they were collected is shown in Table 3.  Lastly, the RBA scores as compared to the Habitat Assessment scores, are important in differentiating low RBA scores due to water quality from those due to habitat quality.  This is illustrated in Figure 2.

 

The following Table 2 addresses Rapid Bioassessment Protocol II metrics, biological condition scores, and impairment assessment for five sites in study.

Figure 2 )  RBA scores compared to Habitat Assessment scores

Table 2

Rapid Bioassessment Protocol II

 

The following table lists the macroinvertebrates collected and the sites that they were collected.

 

Table 3

 

5.0       Discussion

 

The results of this study illustrate the importance of suitable habitat for a healthy macroinvertebrate population.  It also illustrates the effects of harsh water quality conditions (i.e. turbidity and total dissolved solids) on macroinvertebrate populations.  Buffalo Creek (T3), which was selected as the reference stream, scored the highest for both the habitat and biological assessment.  This stream contains all types of habitat sampled within the Wichita River basin.  Water quality is similar as the other sampling sites, but not as high in total dissolved solids as the North Fork and South Fork of the Wichita River.  Therefore, Buffalo Creek was the logical choice for a reference stream in this study.  However, water quality conditions for the North Fork and South Fork of the Wichita River, as well as differences in the types and amounts of suitable habitat  must be addressed.

 

The North Fork (R2) and South Fork (R3) of the Wichita River scored the least of the five sampling sites.  This is due to both harsh water quality conditions (i.e. turbidity, sedimentation, and total dissolved solids), as well as the lack of suitable habitat.  R3 had the least habitat assessment score, as well as the least RBA score.  This site contained some woody habitat and overhanging vegetation, however, these suitable habitats appeared highly susceptible to silt deposition.  This site also had riffle habitat, however, no invertebrates were found in these areas apparently due to the lack of interstitial space caused by fine gravel (i.e. silicon) and clay deposits in between the larger cobble substrate.  The abundance of macroinvertebrates at R3 was minimal, taking two five minute sweeps and five minutes of picking organisms from a submerged log to obtain 22 organisms.  Therefore, it is obvious that R3 is impaired due to both habitat and water quality factors, in that the limited habitat available was negatively affected by the turbidity of the stream.  R2 showed a relatively high abundance, however, the majority (67%) of the macroinvertebrates was collected from riffle habitat, which was suitable for macroinvertebrate colonization (as compared to the insufficient riffle habitat at R3).  Also, 50% of all the macroinvertebrates collected at R2 (71) were of the family Ceratopogonidae.  These Dipteran larvae infested aquatic grasses located within the riffle habitat.  Little is known about the family Ceratopogonidae, making it difficult in determining why these organisms would be infested in this particular habitat.  The larvae are considered predators.  However, some are considered herbivores, which is believed for this particular species and explains their great presence in the grasses of the riffle habitat.

 

The habitat assessment for Beaver Creek (33) and the Wichita River (T5) scored similarly, although Beaver Creek obtained a considerably higher RBA score.  Both of these waterbodies exhibit high levels of total dissolved solids, due to natural brine springs (Wichita River) and the seepage of highly saline water originating from petroleum production (Wichita River and Beaver Creek).  The Wichita River contains a significantly greater concentration of total dissolved solids, which could contribute to the lower RBA score at the Wichita River site (T5).

Another possible reason for this lower score could be that 50% of the sampling at the Wichita River was performed in overhanging vegetation, which was observed to be less suitable for macrobenthic colonization as compared to stable woody habitat.  However, in sampling both overhanging vegetation and woody habitat at T5, a greater taxa richness score was obtained due to the addition of several semi-aquatic species of macroinvertebrates.  Abundance of macroinvertebrates was also considerably lower at the Wichita River station, in that it took twice the sampling effort as the sampling at Beaver Creek to get 100+ organisms.  This is another indicator of impairment at the Wichita River sampling site (T5).

 

Lastly, the scarce presence of species belonging to the notably intolerant families, Ephemeroptera, Plecoptera, and Trichoptera was informative.  This illustrates that the water quality throughout the Wichita River Basin is unfavorable for the majority of intolerant species of macroinvertebrates.  There was sufficient habitat sampled in this study to obtain a good representation of the macroinvertebrates found in this basin, therefore, it is believed that this lack of intolerant species is limited by water quality (i.e. total dissolved solids and turbidity).

 

There were families represented within this EPT index, Hydropsychidae, Odontoceridae, and Tricorythidae.  No families belonging to these three orders were found at R2 and R3, in which the total dissolved solids is the greatest.  This suggests that total dissolved solids may play an important role in limiting the presence of intolerant macroinvertebrates.

 

6.0       Recommendations

 

The results of this study helped in the evaluation of macroinvertebrate populations in the Wichita River Basin (as well as North Texas Region).  However, more studies similar to this study could be conducted for more insight on the macroinvertebrate community.

 

First, seasonal changes in macroinvertebrate populations would be very informative.  Secondly, a study targeting areas with a wider range of total dissolved solids would help in understanding the effects of total dissolved solids on the macroinvertebrate populations.  Lastly, repetition of this study in years to come during the same time period, would help in an overall trend analysis of the biological integrity of the Wichita River Basin.  These multiple datasets will also be helpful in assessing the effects of reducing the total dissolved solids through the Red River Chloride Control Project, as more features of the project are completed and placed in service.

BIBLIOGRAPHY

 

 

Barbour, M.T., J.L. Plafkin, B.P. Bradley, C.G. Graves, and R.W. Wisseman.  1992.  Evaluation

of EPA's Rapid Bioassessment Benthic Metrics:  Metric Redundancy and Variability Among Reference Stream Sites.  Environmental Toxicology and Chemistry.  2:437-449.

 

Harrison, Bill.  1997.  Personal communication through handout.  Texas Natural Resource

Conservation Commission.

 

Lenat, David R.  1993.  A Biotic Index for the Southeastern United States:  derivation and list

of tolerance values, with criteria for assigning water-quality ratings.  Journal of North American Benthological Society.  12(3): 279-290.

 

Merritt, R.W. and K.W.  Cummins.  1984.  An Introduction to the Aquatic Insects of North

America.  Third Edition.  Kendall/Hunt Publishing Company.  Dubuque, Iowa.  862 pp.

 

Parrish, Fred K.  1975.  Keys to Water Quality Indicative Organisms of the Southeastern United

States.  United States Environmental Protection Agency.  2^nd Ed.  Cincinnati.

 

Plafkin, J.L., M.T. Barbour, K.D. Porter, S.K. Gross and R.M. Hughes. 1989.  Rapid

Bioassessment Protocols for use in Streams and Rivers:  Benthic Macroinvertebrates and Fish.   EPA/444/4-89-001.

 

Thorp, J.H. and A.P. Covich.  1991.  Ecology and Classification of North American Freshwater

Invertebrates.  Academic Press, Inc.  San Diego.  911 pp.