Natural Shoreline Restoration for High Energy Shorelines. Brian Majka Restoration Ecologist 3/7/2019

Transcription

1 Natural Shoreline Restoration for High Energy Shorelines Brian Majka Restoration Ecologist 3/7/2019

2 Today we ll discuss: High energy shorelines Restoration techniques for high energy shorelines Project examples

3 What do we mean by high energy Primarily driven by wave height Wind driven waves Boats Wisconsin DNR Low energy=less than 1 foot Moderate Energy=1-2.3 High Energy=greater than 2.3 sites?

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5 Waves break over and lose energy when wave height reaches water depth of 1.3 times the wave height. The gentler the slope, the further off shore the wave will break

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7 How does wave energy affect vegetative growth? Soil erosion Physical displacement of plants Turbidity

8 Warning! Warning! Warning! Waves heights will change as water levels change Great Lakes influenced water levels Wind push Boat waves may be higher than wind driven waves Difficult to quantify Need anecdotal information Planing vs wake boats

9 Critical weight of stone Shoreline slope *12 stone=100 lbs 5 stone =10 lbs 2-3 stone=1 lb Wave height (feet)

10 For the same shoreline, a 1.5 wave will move a ~9 lb stone, while a 6 wave will move a ~0.3 lb stone. But, a 1.5 wave will move a 1 lb stone on a 5 degree slope, but a 10 lb stone on a 30 degree slope Huge design implications

11 Bioengineering uses plants, plant products and special techniques to protect soil surface and create structure within the soil to withstand erosive forces. Overarching concept of any bioengineering technique is the reintroduction of deeprooted native plants, creating a system that mimics naturally stable shorelines. Integrates ecology and engineering

12 STABILIZATION TECHNIQUES: A CONTINUUM OF CHOICES Bioengineering Biotechnical Engineering Structural Engineering Native plants and natural materials Native plants, rock, and erosion control materials Rock, gabions, sheetpile, and concrete

13 DESIGN CONSIDERATIONS Cultural Issues Goals Erosive Forces Ecology Regulatory Concerns Resources (Time, Money, etc ) Form MUST follow function Cost vs. risk Aesthetics Sunlight Habitat considerations (ie, threatened, endangered or rare species) Access to site Soils/moisture Waves/shear stress/erosive forces

14 Common Techniques Erosion control blankets Joint plantings Soil encapsulated lifts Wave breaks/sills/strategic rock placement

15 Let s get this outta the way.. You re probably going to be using rock BUT how you configure the rock can greatly impact the ecology Slope and placement matter Vegetation can be incorporated with rock Plant type matters shrubs are much more resilient

16 Erosion control blankets (ECBs) Product line is extensive for a variety of applications Not all blankets are created equal Blankets containing straw or wood fibers should NOT be used at the water s edge To avoid impacts to shoreline wildlife, choose fully biodegradable netting unless no other options exist

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19 100% coconut with permanent fabric Biodegradable straw coconut

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21 Joint Planting/Native Shrubs Native shrubs Stakes, whips, bare root, plugs Harvesting, handling, storage and pruning considerations First season growth on Red Osier Dogwood live stake

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24 October 2008 October 2009

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27 Prefabricated lift (BioD-Block) Photos: LandscapeOnline.com Construction video at: > Library

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32 Offshore Wave Breaks Strategically placed structure based on water depth and position toward Lake Erie

33 Rock Sills

34 Rock Sills

35 Project Examples

36 Muddy Creek Bay Lake Erie Muddy Creek Bay Sandusky Bay

37 Wave breaks designed to cut fetch and retain sediment Muddy Creek Bay

38 Muddy Creek Bay 10 mile fetch into Lake Erie Strategically placed structure based on water depth and geographic location

39 Marysville Shoreline Restoration St. Clair River Dual-purpose shoreline restoration/public use project Ice push from multiple directions Constructed in of shoreline restoration including 1900 of seawall removal $1.6 million construction cost ($800/l.f.) Project Location Source: City of Marysville.

40 Marysville Shoreline Restoration Source: City of Marysville.

41 Marysville Shoreline Restoration Source: City of Marysville.

42 Source: City of Marysville. Design Solution

43 Source: City of Marysville. Design Solution

44 Establish plants in safe spots, and let them creep out on their own

45 Source: City of Marysville. Design Solution

46 Design Solution

47 Center Point Bay Marina 2 mile fetch Up to ~3 ice sheets ~3 waves recorded at site Ice push from multiple directions Constructed in ,727 of shoreline restoration $822,619 construction cost ($220/lf) Project Location

48 2009 Center Point Bay Marina

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51 2010 Designed gaps for wildlife passage across the land/water interface

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53 2015 Bulrush climbing onto lake bed

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58 4 mile fetch Up to ~3 ice sheets ~6 waves recorded at site Constructed in 2010 D Alcorn Site

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61 BIO D BLOCK

62 BIO D BLOCK

63 BIO D BLOCK

64 In summary: Need to balance functional and ecological goals Plants alone may not cut it Keep the big picture in mind Remember that a failed project benefits no one Don t let the perfect be the enemy of the good

65 THANK YOU!! Brian Majka GEI Consultants, Inc