SESSION D: Stream Connectivity
Session Chair: Josh Royte, The Nature Conservancy
Session Description: The stream connectivity session will describe ecological and societal needs for better connections among our waterways, our oceans and streams, lakes, ponds, and floodplains. Starting with the base ecological need for up and downstream processes we will look at what impedes the movement of water, sediment, nutrient, key structure-forming material (like trees and rocks), as well as fish and other wildlife. We also have societal needs moving drinking water and waste-water from one place to another and for our extensive road networks to safely cross streams and rivers in a way that is cost-effective, yet robust enough to avoid catastrophic damage from normal and our increasingly abnormal storm flood-flows and tidal storm surges. Wherever there are roads and streams that are crossed by them there is greater than a 50:50 chance the road-stream crossing will be undersized and pose both environmental problems for streams and safety and maintenance problems for roads. From understanding the problems to focusing on solutions, this session will look at how Mainers are working together and with restoration practitioners around the country to get better at identifying the most problematic areas for stream ecosystems and societal needs and developing cost-effective lasting solutions. Our goal is to leave 20-30 minutes for feedback and questions and some problem solving on existing and potential assistance for towns and other road-owner/managers such as funding from the 2014 Maine Water Bond.
- Connected rivers and roads: considering climate change in stream connectivity design – Mathias Collins
- Chipping Away at Stream Barriers in Southern Maine – Jacob Aman
- Impact of Culverts on Fish Movement – Ben Naumann
- Case Studies in Restoration of Ecological Connectivity through Culvert Rehabilitation – Mike Burke
Connected rivers and roads: considering climate change in stream connectivity design
Mathias J. Collins, Restoration Center, National Marine Fisheries Service, NOAA
Road-stream crossings are essential components of transportation infrastructure networks. Yet undersized road-stream crossings are known to degrade riparian ecosystems by impeding fish and wildlife passage, sediment transport, streamflow, and other floodplain processes. There is also increasing recognition that undersized crossings are more failure-prone and undermine the resilience of human communities, especially in regions where climate change is expected to increase the magnitude and frequency of extreme precipitation and streamflow events. Thus ecosystem restoration practitioners, community planners, and transportation engineers have a shared interest in climate-informed road-stream crossing design and a stake in the active discussion in the research community about what methods are most appropriate for designing infrastructure for a changing climate. Traditional approaches for estimating design flows assume that the past is a good guide to the future. This is more formally known as a “stationarity” assumption, and presently there are no well-accepted non-stationary design flow estimation techniques. In this presentation I will briefly review observed and predicted hydroclimatic changes in the Northeast U.S. that have implications for road-stream crossing design and discuss a number of recently proposed stationary and non-stationary methods for estimating design flows in a changing climate. The perils of using dated precipitation or streamflow records for project design in New England will be emphasized.
Chipping Away at Stream Barriers in Southern Maine
Jacob Aman, Tin Smith, Dr. Kristin Wilson, Wells National Estuarine Research Reserve
Southern Maine has a long history of dam building dating back to the first grist mills constructed by European settlers in the 1600’s. Many of these structures remain today, creating discontinuities in habitat throughout many small coastal streams in York County. At the same time, development is altering the watershed landscape resulting in adverse impacts to habitat for native species. The Wells National Estuarine Research Reserve waded into the struggle to reconnect stream habitat and improve conditions and over the past five years developed relationships with likely and unlikely partners to inventory stream barriers, secure diverse funding, implement restoration projects, and conduct monitoring. Progress is slow, but steady. We will share the stories of our work to restore stream connectivity working at the local level as a small community based conservation organization, and associated challenges and successes that we have encountered along the way. Specific examples will include stream barrier surveys in three local watersheds, the removal of a small dam on Shorey’s Brook in Eliot, the restoration of a disused fish ladder at the Kennebunk, Kennebunkport and Wells Water District filtration plant on Branch Brook in Kennebunk, ongoing work to remove a head-of-tide dam on a Kennebunk River tributary, and associated environmental monitoring work to track the recovery of target species.
Impact of Culverts on Fish Movement
Ben Naumann, USDA Natural Resources Conservation Service
The Maine public is becoming increasingly more aware of the importance of fish passage and the severe impacts undersized and improperly installed culverts are having on fish movements. To fix problem culverts effecting fish passage, culverts are being replaced with fish friendly structures. Initial cost for fish friendly structures can be alarming and limited annual budgets struggle to augment costs. ractitioners argue that fish friendly structures are cost effective solution overtime for road infrastructure however little analysis has been recently completed here in the state. This analysis examines two road stream crossing case studies common on the landscape, one forestry culvert and one municipality culvert. Estimated accumulative costs for road stream crossing structures included round culverts, arch culverts and bridges were carried out for a duration of 50 years and compared. Preliminary results show for round culverts when carried out 50 years are less economical then other structures overtime due to maintenance costs and replacements. Results also show new technologies, forestry ingenuity and regulations affect what structures are economical overtime. The results of the structure comparison were expected however these structure comparisons can be used as a planning and outreach tool to help change perspectives of fish friendly structures to municipalities and private landowner.
Case Studies in Restoration of Ecological Connectivity through Culvert Rehabilitation
Michael Burke, Nick Nelson, Marty Melchior; Inter-Fluve, Inc.
Stream and river networks in New England have been fragmented by transportation corridors for generations. Addressing the constraints imposed by each individual road crossing on the ecological function of the regional ecosystems is a nearly incomprehensible endeavor. Yet progress is being made, one road crossing at a time. A series of 3 to 4 case studies will be presented of culvert rehabilitation projects that have been successfully implemented in New England (case studies are primarily located in Massachusetts but have similar traits with sites in Maine). The case studies share a common thread of objectives that include restoration of habitat connectivity for a broad range of aquatic and terrestrial wildlife. They differ in the way that the constraints of each location needed to be addressed in the design and construction of the new facilities.