This article from the California Water Blog is a good attempt to deal with what could be and what is, in terms of environmental restoration, with the Delta as the subject.
Estuaries are hard places to understand and even harder to explain. Estuarine scientists, myself included, have struggled to learn how changes in the San Francisco Estuary led to declining fish populations and waning productivity, particularly in the Sacramento-San Joaquin Delta.
We keep searching for what is broken or missing so we can fix or replace it. The thinking is that if we can return or repair these parts of the ecosystem, native aquatic species will recover sufficiently to be resilient in the future.
The trouble is we can’t go back to the way things were more than 150 years ago, before engineers repurposed the Delta’s maze of marshy islands, channels and sloughs for agriculture and water delivery. As fish biologist Peter Moyle has said, “How do you bring back tule or cattail marsh to an island that has sunk 30 feet from decades of farming its peaty soil? You can’t.”
Likewise, fixing what is broken in the Delta has been a daunting if not quixotic pursuit. Scientists for the most part take the classic “reductionist” approach of breaking down complex problems into smaller and simpler units: (1) Identify the ecological features that are damaged or in short or excess supply, (2) pinpoint factors responsible for these problems, then (3) take steps to improve conditions factor by factor or species by species.
This painstaking process has unquestionably improved our understanding of how the Estuary works. But for all the reams of studies produced over the past 30 years we have yet to arrest, let alone reverse, the ongoing decline in pelagic fish populations and ecological health of the Delta.
I propose an alternative but complimentary “reconciliation” approach to restoring the Delta:
Reconcile what we would like to have the Delta be like with what is possible, using our understanding of the historical landscape and its remnant physical features as design guides.
Focus on returning the physical features where ecological processes occur — islands, marshes, deep areas, shoals, shallows, littoral edges, eroding streambeds and riparian corridors — without necessarily worrying about identifying or understanding the precise effect these actions will have on the species of concern.
Put mud flats where mud flats would go, tidal marshes where tidal marshes have been and are likely to endure. Put open water next to shallows.
Work with alien species as part of new, unprecedented estuarine ecosystems.
Return estuary-like features to the estuary and the natural arrangements between geomorphic elements and habitat will re-establish and re-configure themselves. Ecosystems are, after all, self-regulating and self-organizing, even as they change through time. Systems ecologists have struggled to teach us this and we should be willing to learn, given our relative lack of restoration success in the estuary (see Jorgensen 2012).
Retrieved February 23, 2015 from http://californiawaterblog.com/2015/02/19/21st-century-delta-reconciling-the-desired-with-the-possible/