Introduction and Definitions of Restoration

Dr. Mark Stone, P.E.

Definition of Restoration

It is first necessary to define what is meant by restoration in the context of this Wiki. The following definitions are but a few of those used in the fields of watershed and ecosystem restoration:
  • Return an ecosystem to a close approximation of its condition prior to a disturbance (Berger 1990)
  • Act of restoring to the original state or a healthy or vigorous state (Bradshaw 1996)
  • Historic conditions previously existing on the site will be re-established, including the entire function, structure, and genetic composition (NRC 1992)
  • Return of fundamental processes by which ecosystems work, including biological and non-biological elements
  • An intentional activity that initiates or accelerates recovery of an ecosystem with respect to its health, integrity and sustainability (SER 2002)

What all of these definitions have in common are elements of restoring the structure and function of the ecosystem to some historical, pre-disturbance condition. Examples of watershed structure include soil condition, hydrology, water quality, and channel morphology. Examples of watershed functions include water storage, recharge and supply, sediment transport and retention, and transport of organisms, nutrients, and sediments.

Watershed restoration to historic conditions as a goal is typically impractical and prohibitively expensive and there is significant uncertainty and disagreement as to the actual nature of historic or so-called natural conditions. In addition, even if historic or original conditions were better understood, temporal changes in the bio-physical, meteorological (e.g., climate change), and socio-economic (e.g., land uses) and socio-cultural conditions of a watershed or landscape often conspire to drive objectives to alternative outcomes that reflect these realities. More realistically, our goals are to rehabilitate the watershed, which is to return certain functions and structures of the natural ecosystem to a previous state, but not necessarily to the original condition. In this report, we use the term restoration in a very general sense, where we are considering restoration and/or rehabilitation of various watershed structures and functions to meet desired ecological and socio-economic needs.

It is also important to recognize the various ‘types’ of restoration that can be pursued in order to reach an end goal. Here we summarize our interpretation of these activities. Different individuals will likely have slightly different connotations depending on their backgrounds.
  • Watershed restoration is a broad concept that can include a wide range of activities including forest management (e.g. thinning), wetland and riparian restoration, channel alterations, bank stabilization, prescribed burning, and much more.
  • Stream restoration (or stream corridor restoration) includes efforts to improve any aspect of the stream corridor including the floodplains, riparian zones, and the main channel. This is a subcategory of watershed restoration but is still a broad term.
  • Wetland restoration includes the rehabilitation of a degraded wetland or reestablishment of a wetland that has been destroyed. This can be considered part of stream restoration if it falls within the stream corridor (e.g. floodplain and riparian wetlands). Hence wetland restoration can have beneficial impacts on the stream itself. This will typically be the case in the Gila watershed. However, some wetlands are fed by springs or local water sources and are not located in the stream corridor and hence this would fall under the broader area of watershed restoration.
  • Riparian restoration involves improvements to the riparian zone of a stream that aims to enhance functionality and structure of the riparian zone and potentially to the stream as well. The riparian zone is the region at the interface of the stream and terrestrial zone that serves functions (habitat, flood attenuation, etc.) that are dependent on the characteristics of the stream itself (hydrology, disturbance regime, etc.). Thus, adjustments to the stream (physical alternations, hydro-modifications, etc.) will impact the riparian zone and potentially affect its functionality. Likewise, modifications to the riparian zone that impact its functionality will in turn impact the river (negatively or positively).
  • Floodplain restoration can include riparian restoration, but can also include non-riparian efforts such as levee setbacks, acquiring vulnerable lands, removing structures, and other activities beyond the riparian zone.
  • Channel restoration (or in-stream restoration) involves work directly on the stream channel and usually aims to balance channel stability, habitat quantity and quality, and flood control. Examples include channel realignments, bank stabilization, and in-stream habitat or grade control structures.

Connections Between Watershed Processes and Restoration

Watershed restoration is incredibly complex because it requires a systems understanding of every land use at the elementary levels of function and process. A watershed is defined as a large land area that may encompass many political jurisdictions and landowner objectives while containing a mix of ecosystems and land uses (forest, agricultural, riparian, wetlands, urban), that drains surface and groundwater to a downstream water body, such as a river, lake or estuary (Schueler, 2005). One view of a watershed is that it is composed of sub-sheds thought of as landforms, and these landforms are closely related in the same way that the health of a stream channel is closely related to the health of its floodplain, terraces and associated flora and fauna communities (Petersen, 1999). Therefore, the restoration of streams and rivers should not be expected to alleviate problems generated throughout a catchment, given that the problems that lead to stream degradation typically are the result of catchment-scale stressors (e.g., large amounts of impervious cover or land in agriculture) (Bernhardt, 2011). Unfortunately, most restoration efforts are not coordinated at whole watershed scales to maximize environmental benefits and many are not planned strategically, which results in a patchwork attempt to restore a tattered system (Palmer, 2009). Successful watershed management is dependent upon bringing communities of people together, working at the landscape scale to create a common vision for productive and sustainable watershed conditions (RCN, 2002).

Watershed managers and others engaging in science and restoration activities are increasingly planning restoration activities from a systems perspective. This paradigm shift is an outcome of years of research and practice that has informed the restoration community on what does and does not work. Certainly this can be viewed as a positive result of the billions of dollars spent so far on restoration projects. Palmer et al. (2005) defined three forms of restoration success: 1) learning from past efforts, 2) meeting stakeholder needs, and 3) ecological improvements. It is well known that success from a stakeholder’s perspective is relative to each individual. However, watershed planning and restoration is driven by the goals of those that care for the watershed, and so it is critical to align the efforts and resources of stakeholders towards common goals (Cappiella et al., 2006). This form of success is becoming more apparent as community and conservation groups are increasingly taking an active role in the management of their watersheds.

The third type of restoration successes listed above (ecological improvements) is the area in most need of improvement. This area is the focus of much current attention and gaining momentum as our society begins to assert a systems framework to problem solving at many levels. Palmer (2009) describes five ways in which ecological knowledge should be influencing restoration to a far greater extent than at present, including a need to: 1) shift the focus to restoration of process and identification of the limiting factors instead of structures and single species, 2) add ecological insurance to all projects, 3) identify a probabilistic range of possible outcomes instead of a reference condition, 4) expand the spatial scale of efforts, and 5) apply hierarchical approaches to prioritization. These five areas represent the foundation of the paradigm shift that is currently taking hold in restoration practice and research at all levels.

Summary

Watershed restoration is a complex and rapidly evolving field with respect to both research and practice. It is useful to think about restoration in terms of the various types of landforms that can be addressed and the restoration practices that can be employed. However, lessons learned from billions of dollars spent in projects over the past few decades can serve to guide restoration in the Gila Watershed. Specifically, a piecemeal approach to restoration has not produced measureable benefits in most cases. A systematic, basin-wide approach should be employed in the Gila watershed that holistically considers physical, ecological, and socio-economic conditions and aims to build resilience in all of these areas through careful planning and with a solid foundation in science.

References

Berger, J.J. (1990). Evaluating Ecological Protection and Restoration Projects: A Holistic Approach to the Assessment of Complex, Multi-Attribute Resource Management Problems. Doctoral dissertation. University of California, Davis.
Bernhardt, E. S. (2011). River restoration: the fuzzy logic of repairing reaches to reverse catchment scale degradation. Ecological Applications , 1926-1931.
Bradshaw, A. D. (1996). Underlying principles of restoration. Can. J. Fish. Aquat. Sci. 53(Suppl. 1): 3-9.
Cappiella, K., Kitchell, A., and Schueler, T. (2006). Using local watershed plans to protect wetlands. Ellicot City: Center for Watershed Protection.
National Research Council (1992). Restoration of Aquatic Ecosystems. National Academy Press, Washington D.C. USEPA, 2000. Principles for the Ecological
Palmer, M. A. (2009). Reforming watershed restoration: science in need of application and applications in need of science. Estuaries and Coasts , 1-17.
Petersen, M. M. (1999). A natural approach to watershed planning, restoration and management. Wat. Sci. Tech. , 347-352.
Restoration of Aquatic Resources. EPAA841-F-00-003. Office of Water (4501F), United States Environmental Protection Agency, Washington, D.C.
Schueler, T. (2005). An integrated framework to restore small urban watersheds. Ellicot City: Center for Watershed Protection.
Society for Ecological Restoration Science and Policy Working Group (SER), the SER primer on ecological restoration (2002). http://www.ser.org/Primer.pdf. Last retrieved September 13, 2011.