19991233 Ver 1_Staff Comments_20100419

Eaton, Larry
From: Eaton, Larry
Sent: Monday, April 19, 2010 12:08 PM
To: Dorney, John
Subject: review of Preserve monitoring data
As requested I have taken a look at the Preserve's monitoring data. The only trend I could pick out was that the
conductivity steadily incresed at station 2 (the outlet of the southern stream on the property) suggesting some on-
Property water quality degradation in the southern stream.
A couple of problems with the study design make it hard to make sense of the data. First, the one 2000 sampling event,
which did not include all parameters, was the only true before construction sample. Some amount of construction was
occurring in 2001, which may explain the sky high turbidities and phosphorous at SW 1 and SW4 on that date. With one
pre-construction data point, its very hard to tell how much natural variability there was before construction to know,
whether the occassional high numbers post construction are normal.
Second, as far as the bugs go, there is still the single preconstruction sample issue, plus they changed samplers in 2005.
This would explain the water quality improvement in MB-4 - Lenat is a much better sampler- and makes comparisons
between early samples and late rather dubious. I reran the ratings using BAU's new BI rating method for small streams.
About 1/3 of the ratings stayed the same, 1/3 went down one category and 1/3 couldn't calculated because MACTEC
didn't calculate Bis for their samples before 2005'.-56`6' nce again, there is no comparison with before data, though if the
MACTEC data sheets could be found and Bis calculated, that might change some.
Despite the above mentioned issues, a few trends were noted, With the exception of MB-4 and Control (the two control
sites), which rated Good or Excellent) all other streams could be put on the 303(d) list with Fair or Poor ratings for the
last two sampling events. MB-4 showed a consistent decline in total taxa, possibly in part due to the sediment that
impacted this site from upstream off the property in(200&!iDecreased taxa richness without a corresponding increase in
community tolerance is a classic signal for sedimeG tfitib) iissuesihMB-2 (downstream site on south stream) show a
consistent decline in taxa richness, EPT taxa richness and,an increasing tolerance (BI) which may be a biological response
to whatever impact is causing the increasing conductivities at that site. EPT taxa richness at MB-1 (the downstream site
on the north stream), and to a lesser extent total tfa? a ?wdrermuch, higher before and during construction (2000 8 EPT,
2001 19 EPT) than any sample afterward, even wa'thiDaverdoing a better job collecting (post construction maximum 5
EPT), suggesting that something has gone on to seriously stress the aquatic community post construction. This could be
related to the pond that was built immediately upstream of this site.
Given all this, I'm not sure what additional sampling requirements would show, unless it was directed toward identifying
and fixing the degradation in the south stream.
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