Given this issues raised in the short discussion (below) there are policy implications that may (or should ) be applied to Russian River proposed low flow management (and the Biologic Opinion)
First: The Biologic Opinion and proposed low flow scenario were not privy to the findings of the ISRP. They findings should be amended into the Biologic Opinion and any proposed management policy consideration (for consideration of conditions and related effects of proposed management policy). The ISPR provides a the latest and best information as to current and historic conditions – and – must be considered as same in any environment review of proposed management policy.
Next: If habitat conditions in the tribs are, in fact, as described in the IRSP ( essentially devoid of historic habitat necessary to support salmonids in all life stages – see below) – then, in fact, that it may be the case that the mainstem Russian River (and higher than historic natural flows) may be a necessary habitat component to maintain – until such time as the tribs have be rehabilitiated.. That is: Essential flows, shading and near stream habitat, and instream habatat conditions in the trims need to show improvement before any low flow policy should be implemented.
This would require limitation of near stream and instream water diversion in the tribs (especially during the non-rain seasons) and development of near stream canopy for shade and temperature control conditions – and – possibly some restoration work to provide instream habitat conditions (to encourage deeper pools, overwintering habitat, and other refugia, and remval of fish migration blocking obsticles). This work would have to be accomplished and show demonstrable success – prior to the implementation of any low flow policy.
All of these issues must be addressed in the informed decision making process – attendant to CEQA, NEPA, and federal responsible agency mandatory consultation.
Discussion of some IRSP findings – below and arguments to be made:
As the IRSP noted the historic Russian River flows were lower.
However, during that by-gone history things were different – in how the system
Prior to current hydromodification – there was more refugia for fish – both – in the tribs and in the mainstem.
Both – tribs and mainstem – had deeper holes and cooler water. There was more shading on the mainstem and tribs to help keep things cooler in the refugia areas. The tribs had more water (not being pumped dry for Ag irrigation – plus – the rain cycle has changed)- thus providing cooler water and deeper pools for refugia and fish survival in all life stages.
And – finally – the near stream environment had more gravel terraces storing more water and cooler subsurface flows (plus deeper and cooler pools).
All these conditions aiding the life cycle needs of salmonids have been altered (mostly gone).