EXH0589023807

Sent: Monday, July 02, 2001 2:00 PM To: Kenny, Ann Cc: Masters, David Subject: Ecological Input Ann - did get a chance to talk briefly with one of our lead stream ecologist. Here is a summary of some of his recommendations: 1. The proposed mitigation should be evaluated against existing stream hydrology to look for departures from the existing stream hydrograph. His concern is that the mitigations may impose biological cues that could disrupt natural biological processes. For example, a sudden rise in summer flows could imply the on set of winter conditions and corresponding biological responses (e.g., fish moving out of deep pools, etc.). If comparison of existing hydrographs and future hydrographs with proposed mitigation is provided we can look more closely at expected departures from the existing hydrology. This may imply a more gradual on-set of the low flow offset flows, or discharge through wetlands/ponds rather than straight to stream. 2. He was less concerned with mitigation under extreme drought conditions. These conditions happen less frequently and have less influence on biological processes than the more frequent (e.g., 2-year) low flow conditions. He was more concerned with sudden departures from the existing hydrographs than with fully mitigating 100-year type drought conditions. 3. He indicated that water quality (e.g., temperature, DO, pollutants) may be as critical as matching hydrology. Sudden changes in temperature, flowrates, etc. should be avoided. This may imply looking closely at how the reserved water is introduced to the stream (e.g, through ponds/wetlands, or directly to…

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PSCAA Advisory Council Meeting Agenda
Add to CalendarMWednesday Mar 11, 9:00am - 11:35am
1904 3rd Avenue, Suite 105, Seattle, WA 98101
Call to order – Roll Call – Quorum Established – Land Acknowledgement We would like to acknowledge that our Agency operates in four present-day counties, which are the traditional lands of the Coast Salish people, past and present. This acknowledgement does not take the place of authentic relationships with indigenous communities in our jurisdiction and [...]