ACKNOWLEDGEMENTS: Thank you to Eve Vogel for fruitful and enjoyable collaboration on the social/ human/ governance side of this problem. We are grateful to Massachusetts State Geologist Steve Mabee for inspiring us to pursue fluvial erosion hazards in the wake of Tropical Storm Irene and for selfless sharing of data, analysis and ideas; to Andrew Fisk of the Connecticut River Watershed Council for pointing us to a successful citizen’s group interested in the subject, to the Umass Center for Agriculture, Food and the Environment for funding the proof-of-concept project for this work. We are indebted to Mike Kline and the Vermont Rivers Program for getting it right, and to all the people whose stories have helped us along the way. REFERENCES: Rosgen, D. 1996. Applied fluvial morphology. Wiland Hydrology Books, Pagosa Springs, CO; Lane, E. W., 1955. The importance of fluvial morphology in hydraulic engineering. Proceedings, American Society of Civil Engineers, Vol. 81, Paper 745, July.

Agricultural and undeveloped rural forested lands play a crucial role in diminishing the destructive power of floodwaters by receiving, spreading, and slowing the flood wave as it moves through a watershed. Climate scientists predict (and have already observed) that in the Northeastern U.S., individual storms may be more intense, and that there will be more precipitation on an annual basis. The long-term goal of our project is to address the needs of farmers in floodplains specifically relating to fluvial geomorphic hazards and healthy riparian zones along the river corridor by building an integrated support system for farms and rural communities dealing with the uncertainties and destructive power of rivers in extreme weather events. To these ends, we apply a multifaceted research and outreach approach that includes the use of LiDAR and fluvial geomorphic assessments to model stream power in the Deerfield River watershed in Massachusetts and Vermont, where considerable activity and excitement surrounding responsible whole-watershed management is underway. We pair GIS flood prediction analysis with stream power and corridor maps to produce educational materials highlighting the role farms play in floodplains. We integrate our knowledge developed through our prediction analysis with the basin’s agricultural stakeholders in an effort to provide them with best management practices for riparian land management to maximize overall watershed/river health and minimize damages to agricultural lands; we work with agricultural and river management stakeholders through our participatory approach to better river corridor managementto understand how science-based river management policy may be enacted to meet the same goals.

Farms, Floods and Fluvial Geomorphology: Making the most of our natural resources

Benjamin P. Warner, University of Massachusetts at Amherst, bpwarner@umass.eduProject director: Christine E. Hatch, University of Massachusetts at Amherst, chatch@geo.umass.edu

PROTECTING STREAMS AND FARMS IN THE DEERFIELD RIVER WATERSHED: BEST MANAGEMENT PRACTICES

FLUVIAL GEOMORPHOLOGY

ABSTRACT STREAM POWER IN THE DEERFIELD RIVER WATERSHED

PARTICIPATORY APPROACH TO BETTERRIVER CORRIDOR MANAGEMENT

Rivers are dynamic systems which respond to hydraulic driving forces (discharge and slope, plus climate) that tend to erode the bed/banks and the resisting forces (sediment load, particle size, geology, topography, vegetation) that tend to resist erosion. If hydraulic forces increase, the river must increase its sediment load to maintain balance, scouring and changing its morphology to do this. During periods of excessive precipitation, for example, the river will scour the channel until the hydrologic volume or sediment deposition bring the channel morphology back into equilibrium.

Ideally, a river has room to adjust to changes to the hydraulic or sediment regime. Unfortunately, land uses such as floodplain encroachment, channel modifications, lack of a riparian buffer, and artificial bank armoring, for example, which are installed to reduce flooding, can actually cause excess erosion and other deleterious effects leading to an imbalanced river system.

Mapping stream power and fluvial erosion hazard zones show the land adjacent to a river most vulnerable to erosion from flooding based on these principles.

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Figure 2. (a) Map of the Deerfield River watershed. (b) Map presenting stream power across all reaches in the watershed. (c) High stream power area near the confluence of the Deerfield River depicting major deposition on farms after Hurricane Irene. (d) Close-up image of image (c).

Figure 3. We employed participatory action research (PAR) to engage agricultural and river management stakeholders and craft fluvial risk management objectives for Massachusetts. In multiple, structured participatory settings, we crafted a vision statement for our group and a definition of the Massachusetts river corridor, and we analyzed current corridor delineation methods in the context of our definition to develop a Massachusetts river corridor delineation methodology. In addition, we crafted action items to move the fluvial risk management design from planning to application.

Vision statement: The Fluvial Geomorphology Task Force leads the development of tools to guide communities, regulators, and practitioners in the improved, science-based management of Massachusetts river corridors for the purposes of protecting infrastructure, public health and safety, and enhancing ecosystem functions, natural river movement and transport processes.

Definition of the Massachusetts river corridor: The river corridor is the area where channel-driven fluvial processes, including the river’s natural movement of water, sediment, debris and other materials, affect or are likely to affect the landscape, based on current, historic, and projected conditions.

The project team researched and developed best management practices that may allow farmers to better manage and mitigate erosion and deposition on their lands. These BMPs have been presented to farmers and we are working to help interested farmers take these land management steps.1. Keep riparian vegetation intact and aid in the development of native plants to create riparian buffers. 2. Maintain natural woody debris in riparian areas. It can dissipate erosive energy and act as a nursery for aquatic life. 3. Eradicate noxious weeds. They cannot anchor stream banks as effectively as diverse native plants, and riparian areas serve as

corridors for dispersal of invasive species. 4. Develop Multifunctional Riparian Buffers (MRB; Figure 4), which contain staggered vegetation that can harvested for

economic return even if flooded. 5. Plant low-input crops near riparian areas, so that if you lose them you have not lost a significant amount of labor/investment. 6. Plant quick turn-around crops (such as salad greens, etc.) near riparian areas, so that you minimize the window in which flooding

can damage the crops.7. Minimize bare soil. Plant cover crops, native grasses, hedges, shrubs, and trees. 8. Contour farming, contour buffer strips, and no-till farming.9. Size culverts properly to accommodate passage of extreme flows and debris and avoid ponded conditions. Use debris screens

at the inlet and inspect often. 10.Avoid applying pesticides, herbicides, and chemical fertilizers near the riparian area. 11.Locate buildings and material storage away from riparian areas. Depending on the stream, a safe distance might be 50 feet or

100 feet. If the building is located next to a larger river it might be several hundred feet. Source: David J. Welsch, USDA

Figure 4. Multifunctional Riparian Buffer (MRB); BMP #4

Source: John Fellows & Chris Condit

Source: John Fellows

Source: Christine Hatch