Urbanization's Impact on Water Quality & Invertebrate Community of Poudre River - Prof. N., Lab Reports of Botany and Agronomy

Download Urbanization's Impact on Water Quality & Invertebrate Community of Poudre River - Prof. N. and more Lab Reports Botany and Agronomy in PDF only on Docsity! Ann Gibbs Lacey Knapp Katie Toyne Lindsey Banjavcic Brenna Ceron Water Quality of the Poudre River and its Effects on Invertebrate Community Composition Introduction In this experiment, we sampled both upstream of the city and downstream of the waste water plant in order to study the impact of urbanization on the invertebrates species richness and the water quality of the Poudre. The land usages and discharges that were compared include natural forested, urban untreated, and urban treated. Methods Study Sites Urban runoff Water diversions Treated effluent Q Poudre Canyon X Env. L. C. X Swetsville Zoo X Figure 1. This table shows the major influencing factor of the water quality at each site. Figure 2. Site Map Canyon Env.L.C. Swetsville Zoo Site Photos Figure 3. Poudre Canyon Figure 4. Environmental Learning Center mg/L while phosphate increases from 1 to 2 mg/L between the canyon site and Swetsville Zoo. Although specific conductance increases downstream of the treatment plant in both studies, the values we obtained in our experiment are much lower than the values obtained by Voelz. Voelz also noted that dissolved oxygen remained relatively constant in all four sites (between 8.5 and 10.1 mg/L) but dropped slightly between sites 1 and 2; in our study, the dissolved oxygen concentration ranged from 13.2 mg/L at the canyon to 9.26 at the ELC to 14.48 at Swetsville Zoo. In this experiment, we looked at the abundance of invertebrates as well as two different indices to describe the composition of the communities at the three different sites. The overall abundance at the Swetsville Zoo (downstream of the waste water plant) was higher then the reference site in the Poudre Canyon. In contrast, the abundance at the ELC (upstream of the plant), was very much reduced. This suggests that conditions in the reference site (in the canyon) and in the Swetsville Zoo site were favorable to the invertebrates. Also, the %EPT was relatively similar in the canyon and at Swetsville Zoo, suggesting a similar water quality; however, the high %EPT value at the Swetsville site is the result of a large number of Hydropsychidae insects, which are known to be a more tolerant species and could therefore be indicative of a somewhat lower water quality. The %EPT was also greatly reduced at the ELC, but this could result from the limited flowing water and therefore limited space for habitats in which invertebrates could live. The FBI score was lowest at the ELC, suggesting that this site has the highest water quality; however, since abundance was drastically reduced at the ELC, this may not be the best index. The FBI score does increase from the canyon to Swetsville Zoo, indicating higher water quality in the canyon. Our results reflect the results from Voelz et al. (2005). Voelz et al. show a decrease in the percent EPT in their autumn collection of invertebrates (59.3-48.8), but, looking at Fig. 8, our percent EPT seems to be fairly constant from .788 to .79. However, we do see an increase in our biotic index (2-4) as does Voelz et al. (5-5.7). Voelz found a decrease in water quality with increasing urbanization. The tolerant species Hydropsychidae was found in great abundance at the Swetsville Zoo site (the most urbanized), which could indicate lower water quality. These patterns seem to be the result of water diversion and effluent discharge (discharge from a sewer). The ELC site had greatly reduced abundance and flow. This could possibly be due to the diversion of water into the waste treatment plant. At the Swetsville Zoo site, the pattern we see could be the result of effluent discharge from the waste treatment plant. In addition to the effects of urbanization, certain other factors could have influenced the results obtained for invertebrate community structure. As already noted, the very low current velocity at the ELC could have contributed toward the drastically low abundance of insects; in addition, the wetted width at this location was much lower than that of the other two sites. However, after analyzing the habitat data in the appendix, there appears to be no connection between any of the other factors and the biotic composition of the sites. Appendix Habitat Inorganic substrate (% of surber area) Canyon Env. L.C. Swetsville Zoo Boulder (>256mm) 0 0 0 Large cobble (128-256mm) 70 65 50 Small Cobble (64-128mm) 20 20 0 Large gravel (16-64mm) 5 5 20 Small Gravel (2-16 mm) 3 5 20 Sand/silt (<2mm) 2 5 10 Periphyton (% of surber area) Canyon Env. L.C. Swetsville Zoo No visible algae – surfaces rough or slippery 0 0 10 Thin film of visible algae 10 80 0 Thick mat growth 0 0 10 Filamentous algae 90 20 80 Canopy Cover Canyon Env. L.C. Swetsville Zoo Open x Partly shaded x x Partly open Shaded Channel parameters for riffle (measure) Canyon Env. L.C. Swetsville Zoo Wetted width (m) 25 5.5 18.5 Depth at thalweg (m) 0.3 0.3 0.2 Surber sample depth (m) 0.2 0.24 0.17 Surber velocity (m/s) 0.8 0.01 0.5 Inorganic substrate (% of surber area) Canyon Env. L.C. Swetsville Zoo Boulder (>256mm) 0 50 0 Large cobble (128-256mm) 5 25 3 Small Cobble (64-128mm) 30 15 15 Large gravel (16-64mm) 60 5 21 Small Gravel (2-16 mm) 5 5 40 Sand/silt (<2mm) 0 0 21 Periphyton (% of surber area) Canyon Env. L.C. Swetsville Zoo No visible algae – surfaces rough or slippery 10 2 10 Thin film of visible algae 20 3 10 Thick mat growth 60 50 40 Filamentous algae 10 45 40 Canopy Cover