River Delta Adaptive Management Strategy/1. Executive Summary
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Deltas are important and irreplaceable components of the Puget Sound ecosystem. Deltas functions can only be realized where large floodplains enter the sea. Past development practices have reduced historical delta services by 77%, if measured as the area of vegetated tidal wetland. The topography, the character of river discharge, and the biotic communities no longer resemble historical conditions. Sea level and the climate regime that drive river discharge are both changing. In this context, the restoration of delta ecosystem services is uncertain. Responsible investment of public funds in river delta restoration requires that we manage risk around these uncertainties.
The scientific method, when well applied, is a powerful tool for resolving uncertainties in complex systems. A mixture of research, management planning, and adaptive management are necessary to build the scientific evidence that can inform the decisions made by public restoration programs. No single scientific method is likely to provide the needed information, as the kinds of knowledge we need varies. Scientists carefully select the right tool to test and refine a postulate. Therefore it’s important to first identify the uncertainty we wish to mitigate, and then develop the methods necessary to make observations that are precise, accurate, and allow us to make useful comparisons. The Puget Sound restoration community has commonly selected 'monitoring change over time' as the tool of choice for learning, but has found that this method alone may provide very limited predictive power to help us work in complex ecological systems. Concepts like ‘adaptive management’ are referenced in policy discussions, but are poorly defined, and rarely implemented.
This report proposes a framework for organizing science investment to directly support the restoration of delta ecosystems by:
- describing a shared understanding of delta ecosystems,
- synthesizing our current working assumptions about restoration,
- defining a set of topics where we believe uncertainty strongly affects our ability to reliably restore delta ecosystems, and
- defining mechanisms within the Estuary and Salmon Restoration Program to investigate these topics.
We propose three programmatic elements:
- a core monitoring strategy for consistently assessing every project site for problems,
- an approach for implementing learning projects to support decision making, and
- an approach for synthesizing evidence that brings refined postulates and theories into decision making.
Our framework builds on a strong body of recent regional work in Puget Sound and the Columbia River Delta that describes the structures, processes, and functions of delta ecosystems. We propose to organize our learning around six critical dynamics: 1) hydrodynamics and channel formation, 2) sediment dynamics and vegetation, 3) biodiversity and food web development, especially 4) salmonid rearing services, and 5) human social dynamics, especially 6) flood and drainage services. These six dynamics were selected through a series of regional conversations among delta practitioners to discuss the issues that motivate and create uncertainty in delta ecosystem restoration. Each of these dynamics integrates scientific disciplines to define a critical ‘plot line’ affecting our restoration of delta ecosystems.
Within each of these critical dynamics we identify a set of topics and restoration postulates—statements that describe how we believe that deltas function and respond to restoration practices. These topics were selected to describe areas where uncertainty is likely to affect restoration outcomes—they are our greatest sources of risk. By documenting these topics and stating postulates we make explicit our current evidence and our assumptions. By reviewing these postulates, we develop a basis for prioritizing our investments for learning.
We propose that we apply the majority of our regional learning resources toward testing and refining high risk postulates through learning projects, while employing a core monitoring strategy at every new restoration site. Consistent core monitoring allows us to verify that a site is not deviating strongly from restoration goals, allows for detection of some problems, and provides for more robust retrospective analyses. Toward this end our core monitoring strategy, focuses on hydrodynamics, channel formation, sediment dynamics and vegetation. We believe that these dynamics of delta ecosystems provide the best opportunity for rapid assessment, and that biological response, while central to the intent of restoration, is better explored through robust, focused, and carefully designed investigations.
To implement this strategy will require the development of some social infrastructure that is not currently integrated in our restoration systems. Evaluation and scoping of proposed learning projects, and review and synthesis of products, requires some form of scientific peer review. Due to the close social networks within the Puget Sound community, we propose that we draw from a broad regional scientific and policy community base, and include some refereed blind review, so that skilled and knowledgeable reviewers are free to provide robust critique without fear of provoking social conflicts. In addition we are developing a web-based information sharing platform, using a minimally structured open-source user-generated information platform (Mediawiki) to allow for rapid and efficient exchange and synthesis of documents, data and ideas among a diverse community.
These new elements—core monitoring, learning projects using peer review, and information sharing—will be integrated into existing ESRP project management practices. We anticipate that this will not only increase the efficiency of ESRP restoration science investments, but also provide a regional platform for supporting investment in river delta science by a range of stakeholders, with a high level of accountability.
Finally, we propose an initial approach for standardizing the policy level accounting of delta restoration, with a focus on tidal elevation zones, and the restoration of tidal flow. The proposed methods combine Puget Sound Nearshore Ecosystem Restoration Project data products, with more recent LIDAR based DEM topography being developed by the US Geological Survey. New data will continue to provide new opportunities for evaluating whole delta conditions. However we believe that these existing resources can be efficiently applied to provide an overview of current delta condition and the status of ecosystem restoration, rather than a out of context list of projects.