Aquatic System - Toronto and Region Conservation Authority

FMZ 2: Berczy CreekFigure 8-12 summarizes the existing conditions of Berczy Creek (FMZ 2) located in theheadwaters of the Rouge River watershed. Overall, the habitat in the zone is of high quality,evidenced by an abundant redside dace population present in the lower reaches of BerczyCreek likely maintained by the presence of local groundwater discharge. There are no brooktrout in this zone as the headwater habitat is generally warmer relative to adjacentsubwatersheds. There is an instream barrier that splits the available redside dace habitat,allowing only downstream movement of redside dace as they can not re-negotiate the barrierand return to upstream habitat. Both rainbow trout and brown trout are stocked above thisbarrier into redside dace habitat. Sampling records have found adult rainbow and brown troutabove the barrier, so it is assumed that these species are able to jump the existing structure.Upstream landuse is largely agricultural with limited forest cover which may be a factor inwarmwater conditions persisting in upstream reaches. Multiple golf courses are also presentwhich can have impacts on water quality/quantity and loss of riparian vegetation.Stream Health: FMZ 2Table 8-9 summarizes the indictors of stream health for Berczy Creek (FMZ 2). Aquaticsystems warm with downstream progression unless, as in Berczy, large amounts ofgroundwater discharge occur along the way. The cool- warm trend in Berczy is interrupted midwaythrough the zone as groundwater inputs modify the habitat and we see populations ofredside dace supported. The stream data (IBI and CCA scores) mark this trend with “fair’ to“good” ratings upstream and downstream of the discharge zones, respectively, with thefurthest downstream habitat becoming warmwater.The unstable temperature calculation in 2005 is confined within the short warmwater reachabove the groundwater discharge zone, suggesting upstream impacts maybe occurring inaddition to the natural warming gradient. However, the groundwater appears to mitigate theupstream warming trend at the reach level. The benthic invertebrate data follows a differenttrend with the impaired site occurring within the discharge zone and the non-impaired sitescoincident with only “fair” IBI ratings. The confounding issues around benthic invertebrates arediscussed in Appendix A and from that, it is possible that the benthic communities in thesesites are more sensitive to habitat than water quality.Table 8-9: Stream Health of Berczy Creek - FMZ 2Target SpeciesRSD, ABL, BM, RDIBI RatingBAA RatingTemperature RatingCCA CA Score2003 2005 2003 2003 (OSAP) 2005 (Wehrly) 20020 VG1 G3 F0 P0 VG1 G0 F0P2 unimpaired1 impaired3 mod stable 2 mod stable1 unstablewarm: mid-rangeNo. Stations 4 1 2 3 3Note: the listed “year” indicates from which data set the ratings/scores are based upon. 2003 IBI combines RWMPand FMP stations sampled in that year. 2005 IBI are only FMP stations. See Figure 8-5 for IBI Station Locations. VG=Very Good, G = Good, F= Fair, P = Poor.8-35