APPENDIX F

 

AN ASSESSMENT OF BIOLOGICAL INTEGRITY

RED RIVER BASIN REACH I (EASTERN)

 

Bowie to Montague Counties

April 1998

 

BASIN SUMMARY REPORT

FOR THE

RED RIVER BASIN

September 1999

 

 

1.0       Abstract

 

This paper gives insight into the biological health of streams located in the eastern Red River Basin in Texas.  Little information exists on the biological communities of this geographical region, which hinders long-term comparisons.  Hence, both fish and aquatic macroinvertebrates were collected during the summer of 1997 to enable the calculation of  biological indices and provide a biological survey for future reference.  Rapid Bioassessment (RBA) methodologies were used for the quantification of biological integrity at 10 monitoring stations in this region.  Results show good overall biological health of the selected streams in this region, with some moderate impairment.  Both fish and macroinvertebrate indices showed similar results in most cases.  Detected impairment is most likely due to physical habitat limitations, rather than water quality problems. 

 

2.0       Introduction

 

This paper presents the results of a bioassessment study of the eastern Red River Basin in Texas.  The study was performed under a monitoring plan developed under the Texas Clean Rivers Program (CRP).  Under this plan, biological monitoring plays a major role in supplementing chemical and physical data to provide a complete assessment of water quality in the Red River Basin.

 

The primary objective of this study was to assess the water quality of streams within the eastern Red River drainage in Texas.  Collections of fish (Exhibit A) and aquatic macroinvertebrates (Exhibit B) were collected at 10 sampling stations, which encompass the entire eastern region of the Red River Basin.  These biological collections were then used to calculate a biological integrity score, using RBA protocols (Plafkin et al., 1989).  By performing habitat assessments at these stations, it is possible to determine biological impairment due to water quality, as opposed to natural habitat characteristics.

 

Table 1 provides a description while Figure 1 shows a map of these stations, which are exposed to several different land uses having the potential to impair water quality.

Table 1

Description of Monitoring Stations Sampled for Biological

Communities in the Eastern Region of the Red River Basin

 

 

                        U ) Urban Activity            F ) Farming Activity    R ) Ranching Activity

 

These include urban activities, such as wastewater effluent discharges and stormwater runoff carrying excess nutrients and pollutants.  Secondly, these stations encounter to a varying degree, the potential degradation from farming activities, including sedimentation and excess runoff carrying various pollutants.  Lastly, these stations are exposed to ranching activities, which result in sedimentation, introduction of fecal pathogens, and deterioration of the riparian zone/streambanks.  Table 1 displays which of these activities are predominant at each of the monitoring stations.

 

3.0       Regional Description

 

The eastern portion of the Red River watershed is from the Texas-Arkansas state-line upstream to the confluence of Cache Creek and Red River (Bowie County to Montague County).  There are five subwatersheds in the reach totaling 7,698 square miles of contributing drainage area in Texas, Arkansas and Oklahoma (3,600 square miles in Texas).  Average annual rainfall for this region is approximately 30 to 40 inches a year.  The streams of this region are generally low-gradient and possess clay/silt substrates.  Vegetation presence is moderate, dominated by hardwoods and grasses.  Overall physical habitat in this region is supportive for biological communities to thrive.  Limiting habitat characteristics for aquatic life in this region include the lack of suitable habitat and poor bank stability.

Figure 1  a map of these stations

 

4.0       Methods and Materials

 

4.1Rapid Bioassessment Methodology ) Macroinvertebrates

 

Pollution tolerance values for macroinvertebrates were assigned based on values established by the Texas Natural Resource Conservation Commission (TNRCC) (personal communication ) 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 and Cummins, 1996, Parrish R.K., 1975, and Thorp and Covich, 1991).  The data thus recorded were used to score seven metrics for a slightly modified RBA Protocol II (RBP II) (Plafkin et al., 1989 and Barbour et al., 1992).

 

Data Analyses

 

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 genus,

t_i      =          tolerance value for the taxa,

n      =          total number of organisms in the sample.

 

5.   Percent Contribution of Dominant Taxa = 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 compared to the total metric score for the reference site to obtain the percent the reference site to obtain the Percent Comparability to Reference Site value.  The reference site in this study was Mud Creek, due to its superior biological and physical health, as well as minimal environmental disturbances.

 

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 site.  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.

 

Sampling Methodology

 

The sampling methodology for this study consisted of using a D-framed kicknet to sweep woody habitat, vegetation, and to 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 was conducted.

4.2Rapid Bioassessment Methodology – Fish

 

Fish species were identified and assigned origin groups, tolerance values, and trophic levels (Plafkin et al, 1989; Hubbs, et al, 1991).  This information was used to score 11 RBP V (or IBI) metrics (Plafkin et al, 1989).  RBP V allows for some discretion in selecting individual metrics for analysis.  The metrics used to calculate an IBI score for these stations was a modified version developed for fish in the Subhumid Agricultural Plains of Texas (Ecoregions 27, 29 and 32) (Linam ) personal communication).

 

Data Analyses

 

The 11 metrics which were evaluated in this study were:

 

1.           Total Number of Species

2.           Number of Cyprinid Species

3.           Number of Sunfish species

4.           Number of Benthic Invertivore Species

5.           % as Tolerants

6.           % as Invertivores

7.           % Piscivores

8.           % Omnivores

9.           Number of Individuals

10.% of Individuals As Non-Native Species

11.% Diseased/Anomalies

 

All metrics, except "total number of individuals" were scored according to the previously cited references.  The "total number of individuals" metric was changed due to different seine mesh sizes being used in this study as compared to mesh sizes used at stations at which the metric scoring criteria were calculated.  Smaller mesh sizes were used at stations used in calculating the metrics, resulting in a greater number of fish to be collected (i.e. western mosquitofish).  A score of one would have been obtained for this metric at all stations, therefore, an alternate methodology was used.  The total number of individuals from each of the 10 stations were ranked and the value at the 90^th percentile was deduced.  This number was split into thirds, giving the three ranges for the metric scoring.  This is consistent with the methodology used for the calculation of other metrics.

 

The metric scoring consists of each metric receiving a 1, 3, or 5, based on its numeric value.  The 11 metric scores for each sampling site were totaled to obtain an Index of Biotic Integrity score.  Each sampling site was classified as being in Limited (<35), Intermediate (35-40), High (41-48), or Exceptional (>48).

 

Sampling Methodology

 

Fish were sampled at each site, using a backpack electro-shocking unit and/or seining techniques.  Due to differing conductivity levels and habitat, a consistent fish sampling methodology could not be implemented.  The normal protocol for fish sampling calls for 15 minutes of seining and seven seine hauls.  However, if electro-shocking could not be conducted, then 10 seine hauls were performed.  Additional seine hauls were performed if a new species was collected in the final seine haul until a seine haul with no new species occurred.  Sampling gear consisted of a Model 12-B Backpack Electro-fisher, a 10 foot seine with ¼ inch mesh, and a 25 foot bag seine with ¼ inch mesh.

 

All habitats, such as snags, rootwads, riffles, and undercut banks were sampled, if present, in order to maximize the capture of different fish species.  A representative of each species was preserved in 10% formalin solution and returned to the lab for identification.  All other fish collected were released, unless identification could not be performed in the field.  All fish were identified to species and the number of each species was recorded.

 

5.0       Results and Discussion

 

The overall biological integrity for this geographical region falls into the moderately impaired category.  The results shown in Table 2 indicate good overall biological health for the streams of the eastern region of the Red River Basin.  RBA (invertebrates) scores range from 57.1 to 100, with the majority showing moderate impairment.  RBA (fish) scores ranged from 29 to 49, with most scores falling into the intermediate to high categories.  It is evident that anthropogenic activities are not extensively degrading the biological health in this region. However, impairment was detected in using these protocols.  It is also evident that physical habitat conditions at these stations are far less than optimal, namely due to the lack of favorable substrate and varying flow regimes for both fish and macroinvertebrates.

Table 2

RBA and Habitat Scores for Stations Sampled

in the Eastern Portion of the Red River Basin

 

 

 

The flows at stations Bois d'Arc Creek at FM 100, Pine Creek at FM 2648, Choctaw Creek at Highway 69, and Big Mineral Creek at FM 901 are heavily influenced by municipal wastewater discharge.  The results of this study show that the water quality of these streams are supporting aquatic life communities similar to creeks not heavily influenced by wastewater effluent.  Wastewater discharge from the City of Whitesboro sustains the healthy biological community at Big Mineral Creek at FM 901 (as compared to Big Mineral Creek off of US 377).

 

The station Big Mineral Creek off of US 377 scored poorly (Limited) for the health of fish communities.  The poor RBA (fish) score for this station can be attributed to natural conditions.  The flow at this site is intermittent with perennial pools.  The perennial pools are usually small, shallow pools and would explain the poor biological integrity.  The benthic community at this station showed only moderate impairment with a score of 64.3.  This contrast is most likely due to the fact that macroinvertebrates can sustain healthy communities more easily in these low flow conditions, as compared to fish.  It is also noted that it took twice the sampling effort (10 minutes) to get an adequate number of macroinvertebrates to calculate a valid RBA score.  This low abundance is not considered in the score, however it can be a sign of impairment.

 

The station Red River at I-35 also scored poorly for the health of its fish community.  This is attributed to natural conditions.  It is obvious that the fish communities inhabiting the waters at Red River at I-35 will not be similar to those found in the fresh water tributaries sampled in this study.  The environment of the Red River is characterized by saline water and poor habitat to sustain a diverse aquatic ecosystem.

 

The station Pine Creek located approximately 0.75 miles downstream of US 27 showed interesting results.  The RBA (invertebrates) had the lowest score (57.1) of all stations, while the RBA (fish) scored "High" (41).  The habitat assessment score was relatively high among all the stations, which gives evidence that natural habitat conditions should be able to sustain healthy macroinvertebrate communities.  Not only was the Pine Creek score the lowest, it also took twice the sampling effort to collect only 45 individuals.  This gives question to the validity of the calculated RBA score and the macroinvertebrate health at this station.  All water quality data in the TNRCC Surface Water Quality Management database for stations on Pine Creek and in the near vicinity were scanned with no evidence of poor water chemistry.  Future collections for macroinvertebrates at this station will provide additional information in determining the cause of this uncertainty.

 

The metric "Number of Macroinvertebrate Taxa" ranged from 14 to 31, which is good to moderate for this region.  Most of these taxa are relatively tolerant, which is indicated by the metric, "Family Biotic Index".  This metric ranged from 6.0 to 7.7, which is characteristic for waterbodies located in this area.  Taxa belonging to the "intolerant" orders of Ephemeroptera, Plecoptera, and Trichoptera were very limited, as would be expected.  The number of genera belonging to these orders ranged from 0 to 3.

 

All stations scored high for the metric "Scraper to Filterer Ratio".  This is due to the lack of taxa belonging to the "Filterer" Functional Feeding Group (FFG).  Elevated percentages of taxa belonging to this group is indicative of enrichment to the stream.  The only two stations that had any substantial numbers of filterers were Pine Creek at FM 2648 and Big Mineral Creek at FM 901.  Both have base flows heavily influenced by wastewater effluent.  The consistent presence of taxa and percentages of functional feeding groups indicates moderate to good health, as indicated by the two metrics, "Community Loss Index" and "Quantitative Similarity Index – Functional Groups".  Streams exhibiting impaired water quality conditions would most likely possess different taxa (and FFG percentages), as compared to the reference site.

6.0       Conclusion

 

Good overall biological integrity characterizes the eastern Red River Basin in Texas.  Detected impairment obtained through the calculation of RBAs can be attributed mostly to natural conditions (i.e. poor natural habitat).  Anthropogenic activities do play major roles in water quality and quantity in this area, however, not in a negative manner.  In some cases, man's activities actually sustain flows needed for healthy biological communities to flourish.

 

These stations will be revisited at a later date, in order to detect long-term trends in  quality for this region of the Red River Basin.

BIBLIOGRAPHY

 

 

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