Aquatic Ecosystem Response to Storm Water Abatement Measures in the Ravines of the GVSU Allendale Campus: Establishment of Base-line Biological Condition

The ravine tributary streams surrounding Grand Valley State Universities Allendale campus represent unique and understudied ecosystems, worthy of significant restoration efforts and of long-lasting protection. They are variously affected by storm water runoff, representing a spectrum from severely impacted to relatively pristine. Quantitative macroinvertebrate samples taken from six streams in late June 2007, indicated that insect diversity was positively correlated to ammonium (p=0.057), while total abundance was negatively correlated to phosphate and chlorophyll-a concentration (n.s.). In addition, phosphate, nitrate, sulfate and iron concentrations were elevated in streams that experience significant storm-water runoff and these streams also tended to have lower macroinvertebrate abundance, diversity and richness. These elevated nutrients, phosphorus in particular, were rapidly taken up by the benthic algae as evidenced by declining nutrients, and increased algal pigment and organic matter concentration from up to down-stream (n.s.). Biological uptake did not translate into increased macroinvertebrate abundance, likely because of the flashy discharge regime. Combination of non EPT (Ephemeroptera, Plecoptera, and Trichoptera) metrics indicated that the Shire and Junkyard ravines were in better condition than sites at Isengard and Fangorn—patterns which strongly suggest that extent of storm-water runoff has negatively impacted the macroinvertebrate communities. The fish community assessment indicated that blacknose dace (Rhinichthys atratulus), a species known to prefer cold, clean water, was most abundant in the Shire—the most pristine ravine stream sampled. Comparing length/weight data in the sampled streams to state standards indicated that these dace are not as fit as typically found in other water bodies whereas other taxa, namely the white sucker (Catostomus commersonii) and creek chub (Somotillus atromaculatus) are indistinguishable from state fitness standards. We were successful establishing biological base-line conditions prior to the initiation of a campus wide storm-water abatement program and can use these benchmarks to gage the long-term efficacy of restoration using physicochemical, population, community and ecosystem functional attributes measured in these unique ecosystems