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BELLE ISLE COMPREHENSIVE HYDROLOGIC ASSESSMENT2

01

6

Prepared by: Prepared for:

1| Overview

Report Objectives ...........................................2

2| Background

History .............................................................6

Timeline ........................................................8

3| Inventory and Analysis

Data Collection .............................................10

Flatwoods Systems Analysis ........................12

Hydrology ....................................................12

Land Use ....................................................23

Utilities .......................................................27

Soils ............................................................28

Terrestrial and Aquatic Systems ...............28

Summary of Findings ................................31

Flatwoods Wide Restoration Strategies ...33

Flatwoods Enlargements-Analysis and Recommendations .......................................34

Summary of Findings ................................56

Next Steps .....................................................57

4| Bibliography

TABLE OF CONTENTS

1 | OVERVIEW

REPORT OBJECTIVESIn response to tasks 2A and 2B of the Lake Okonoka Habitat Restoration project, this report aims to gain an understanding of the current hydrology on

• Expansion of the island by approximately

Construction of Lakes Muskoday, Okonoka and the Blue Heron Lagoon

•

recreation purposes changed drainage

•

•

disruptions, but most are only partially

•

• Buildings, recreational uses and parking

•

• Emerald ash borer decimated one of the

Phalaris arundinaceaLonicera maackii

Phragmities australis

2 | Overview

Belle Isle Projects

of subtask to aid them in understanding the

• documents on the site infrastructure including the lake and canal pumping

• for the impacted lakes and, if possible,

• Supplement existing topographic and

•

•

• if Lake Okonoka is connected to the

• and abandoned roads and trails on the

•

•

either directly or indirectly through the analysis

Belle Isle Comprehensive Hydrologic Assessment | 3

• Flatwoods Systems Analysis

and human introduced systems are

systems analysis focuses on describing

systems are described generically and

• Detailed Flatwoods Systems Analysis

shaping the current characteristic of

is necessary since the scale of the

• Restoration Strategies

strategies are presented under

considered data that is part of the next

• Next StepsA list of needs and priorities are presented to guide next phases of

4 | Overview

2 | BACKGROUND

Figure 1. Historical Survey

HISTORY

6 | Background

Figure 2. Historical Bathymetry

occupied the region, but little information

Accurate mapping of the island extends back


TIMELINE •

•

• Canal and Lake Construction

• City of Detroit Water Intake System

•

• House

•

•

•

•

•

•

•

•

•

•

the importance of maintaining the

recreation amenities and infrastructure

8 | Background

3 | INVENTORY AND ANALYSIS

DATA COLLECTION

• Buildings, structures and some utilities

• Roads, trails and foot paths

•

• Drainage ditches

• Some drainage pipes

•

•

to the introduction of the emerald ash

• Additional trails and foot paths

• Additional drainage ditches

•

•

• Site utilities

• pipes

10 | Inventory and Analysis

TRAIL

DITCH

EXISTING STANDING WAATER/VERNAL POOL

EXPANDED STANDING WWATER/VERNAL POOL

STORM WATER PIPE

TREELINE

POOLED WOOLED WATER IN LAWN

OVERLAND DRAINAGE FLOW

SPOT ELEVATION

LEGEND

Figure 3. Existing Conditions Survey (Circa 1990’s)


has become clear that there are a number of changes both natural and human introduced

under this analysis section describe and depict

described under the Detailed Flatwoods Systems Analysis

Hydrology

Canals and Lakes

Land Use

Buildings and Site Features

Utilities

Soils

Emerald Ash Borer

Herpetofauna

Mammals and Birds

Species

FLATWOODS SYSTEMS ANALYSISHYDROLOGY

•

•

•

• Canals and Lakes

•

PONDING

canopy trees is important since these trees


Figure 4. Forest Hydrology-Pools

LEGEND

TING STANDING WATER/VERNAL POOLEXIST

ANDED STANDING WATER/VERNAL POOLEXPA

REELINETR

OOLED WATER IN LAWNPO


Fraxinus spp. Acer spp.Lindera benzoin

though topography suggests that it should and ditching appears to be the cause of this

Lonicera maackii

TOPOGRAPHY AND DRAINAGE PATTERNS

that represented a gradual transition from

discussed throughout this analysis section,

•

•

•

•

•

•

• Emerald ash borer

• Soils

many areas for most of the spring and summer

some areas currently are holding too much

buttresses


BELLE ISLE AS MAPPED IN 1997

BELLE ISLE AS MAPPED IN 1882

FLATWOODS TODAY

HISTORIC FLATWOODS

LEGEND

Figure 5. Historic Belle Isle & Flatwoods Overlay


HISTORIC WETLANDS

HISTORIC HYDROLOGIC FLOW PATTEERRRNNNSSS

LEGEND

Figure 6. Historic Drainage Patterns

reduced most to all of the pools to saturated altered and is discussed further in the Land Use


Figure 7. Slope Analysis


more accurate topographic information and tree locations and species can be plotted and

DETROIT RIVER INFLUENCE

Until the introduction of the internal lakes and canal pumping system that regulates the

hydrogeologists and engineers to understand

•

•

•

•


ORRDINARY HIGH WATER ELEVATION - 96.9

100 YEAR FLOOD ELEVATION - 98.0

LEGEND

Figure 8. Historic Belle Isle & Flatwoods Only


CANALS AND LAKES

berms around their perimeters for roads and

pump station upstream from Lake Muskoday

case, the pumps are intended to run for some length of time on a regular basis to supply fresh

current plans to do the same for Lake Muskoday and the canal system, although the pumps are

construction has intercepted historical surface

the Ditches and Culverts

DITCHES AND CULVERT

created by the construction of the numerous roads, bridle trails and foot paths installed

Level 1.


DIITCHES & CULVERTS - LEVEL 1




CUULVERT PIPES

SUUSPENDED CULVERTS

DIITCHES

DIITCH OBSTRUCTIONS/HIGHPOINT

2

*

2

22

2

*

LEGEND

Figure 9. Ditches & Culverts


Level 2.

opposite direction of the historic drainage

generally drain in the direction of the historic patterns, except that they are intercepted by the

Level 3.

historic drainage patterns, except that they are

Level 4.

In more than one location, fallen ash trees or

location and in the remainder, are associated


LAND USE

• Buildings and Site Features

•

•

BUILDINGS AND SITE FEATURES

• Belle Isle Nature Zoo including Parking and Animal Enclosures.

site and has changed historic drainage

• Former Golf Course and Related Structures. Historically, this area

be seasonally maintained, suggesting

• Oakway Trail Comfort Station and Parking Lot. Currently closed, the structure is in need of major

suggesting restoration opportunities

• Picnic Areas west of the Oakway Trail Comfort Station.

hydrology and suggests restoration

• Former Safari Zoo and Related Structures.

majority of the facilities located on the

Safari Zoo footprint in this location is located along one of the highest natural

and changed topography is present and

• Athletic Courts and Field.contains a concrete handball court,


CENTRAL AVENUE

CENTRALCENTRAL

AVENUE

AVENUE

OAKWAY

THE STRAND

THE STRAND

LAKESID

E DRIVE

LAKESIDE DRIVE

RIVERBANK DRIVE

RIVERBANK DRIVE

MEA

DO

W

ROA

D

INSU

LRUH

E

AVENU

E

SHADOWNOOK

STREET

TANGLEWOOD DRIVE ABANDONED

WIL

DW

OO

D P

ASS

WILDWOOD PASS

DOSSIN GREAT LAKES MUSEUM

FORMER HORSE STABLES

WHITE HOUSE

GREENHOUSES MODEL YACHT BASIN

U.S. COAST GUARD STATION

SOUTH FISHING PIER

NORTH FISHING PIER

DETROIT YACHT CLUB

CITY OF DETROIT WATER INTAKE

CENTRAL INTAKE STRUCTURE

BEACH

CONSERVATORY / AQUARIUM

ATHLETIC FIELDS

ATHLETIC SHELTER

FORMER ZOO

BELLE ISLE NATURE

ZOO

SYLVAN CANAL

NASHUA CANAL

NASHUA CANAL

WET-MESIC FLATWOODS

FUTURE WELCOME CENTER & BEAR PIT COMFORT

STATION

LAKE OKONOKA

PICNIC AREA

WOODSIDE COMFORT STATION

LAKE MUSKODAY

BLUE HERON LAGOON

LIVINGSTONE MEMORIAL LIGHTHOUSE

COURTS & FIELDS

CANOPY TREES & LAWN

FORMERORMERERER ZOOOOO

SAFARI

MEA

MEA

DM

EAD

MMEA

DDM

EAD

MO

W

OW

OOW

OW

OW

OW

ROA

DD

CANOPY TREES &

LAWN (PICNIC AREA)

OAKWAY TRAIL COMFORT STATION

& PARKING LOT

FORMER GOLF COURSE

FORMER GOLF COURSE

LEGEND

Figure 10. Land Use Analysis


extending into the natural areas, the

around the entire perimeter and along

• Woodside Comfort Station.structure has no current impacts on

that minor ditching has occurred to the

the Lake Okonoka Habitat Restoration

• Picnic Area. Much like the former golf course, this use occupies part of the historic drainage patterns for the south

original topography has been altered

abandoned picnic structures and slabs

Habitat Restoration project, the eastern

• Roads, Parking and Pedestrian Trails.and trail systems extend throughout

thought on maintaining pool hydrology

• Roads and Parking.asphalt road system and contiguous

complexes on the north and south

that block historic drainage patterns and create upland shoulders that

been constructed on less than 2 feet

these locations to address drainage but

the concerns about pool hydrology and


CENTRAL AVENUE

CENTRALCENTRAL

AVENUE

AVENUE

OAKWAY

THE STRAND

THE STRAND

LAKESID

E DRIVE

LAKESIDE DRIVE

RIVERBANK DRIVE

RIVERBANK DRIVE

MEA

DO

W

ROA

D

INSU

LRUH

E

AVENU

E

SHADOWNOOK

STREET


WIL

DW

OO

D P

ASS

WILDWOOD PASS

DOSSIN GREAT LAKES MUSEUM

FORMER HORSE STABLES

WHITE HOUSE

GREENHOUSES MODEL YACHT BASIN

U.S. COAST GUARD STATION

SOUTH FISHING PIER

NORTH FISHING PIER

DETROIT YACHT CLUB

CITY OF DETROIT WATER INTAKE

CENTRAL INTAKE STRUCTURE

BEACH

CONSERVATORY / AQUARIUM

ATHLETIC FIELDS

ATHLETIC SHELTER

FORMER ZOO

BELLE ISLE NATURE

ZOO

SYLVAN CANAL

NASHUA CANAL

NASHUA CANAL

WET-MESIC FLATWOODS

FUTURE WELCOME CENTER & BEAR PIT COMFORT

STATION

LAKE OKONOKA

PICNIC AREA

WOODSIDE COMFORT STATION

LAKE MUSKODAY

BLUE HERON LAGOON

LIVINGSTONE MEMORIAL LIGHTHOUSE

COURTS & FIELDS

CANOPY TREES & LAWN

SAFARI

CANOPY TREES &

LAWN (PICNIC AREA)

OAKWAY TRAIL COMFORT STATION

& PARKING LOT

FORMER GOLF COURSE

FORMER GOLF COURSE

LEGEND

Figure 11. Roads, Parking & Pedestrian Trails


• Trails.

historic trail system constructed for

the abundance of honeysuckle that has

UTILITIES

sanitary, storm, electric, natural gas and

Belle Isle Master Plan -Technical Assessment Report, Part 1

the Lake Okonoka Habitat Restoration project

•

inch mains and the perimeter loop roads

•

as described in the Roads and Parking

•

determine their discharge points and either drain to the lakes or discharge

•


SOILS

reports taken from Belle Isle, hand dug test

for the presence of saturated or seeping soils

TERRESTRIAL AND AQUATIC SYSTEMSUnderstanding the composition of terrestrial and

process by focusing on the relationships of the

TREE CANOPY

•

While further study on this topic is still

suggesting that the aerial extent of

occurrence or is the beginning of a trend

•

that a number of oak species and some

attributed to the presence of prolonged

locations are described in greater detail in the Flatwoods Enlargement Analysis

•

ahead of the healthier stand of trees,


these trees are exhibiting stress related changes

acclimation, climate change, disease and insect

as part of the next phase of studies for the

SPECIES DIVERSITY

Tree Survey and Plant Lists for the Woods of Belle Isle Park

• At the time of the report, emerald ash

Fraxinus

by the genus Acer Quercus

• included Acer saccharinumFraxinus pennsylvanicaQuercus palustris

•

•

blanketed much of southeastern

are fortunate that foresighted leaders

EMERALD ASH BORER

•

Phalaris arundinaceaLonicera maackii

Rhamnus cathartica

•

Fraxinus profunda

• at least three locations, increasing the amount of ponding trapped behind the

• Reduced transpiration could be linked to


XISTING STANDING WATER/VERNAL POOOLLLEX

XPANDED STANDING WATER/VERNAL POOOOOLLEX

REELINETR

TTREES EXHIBITING STRESS

CENTRAL AVENUE

OAKWAY

THE STRAND


WOODSIDE DRIVE

OAK & MAPLE UNDER STRESS

YOUNG MAPLE UNDER STRESS

OAK & MAPLE UNDER STRESS

MULTIPLE DEAD RED OAK TREES

OAKS UNDER STRESS

MIX OF TREES UNDER STRESS(MOSTLY OAK)

MAPLES UNDER STRESS

OAKS UNDERSTRESS

SEVER DIEBACK. SILVER MAPLE AND OAK

LEGEND

Figure 12. Tree Assessment


•

hydrology

• reptiles and amphibians currently occupying the pools and detritus created by fallen and decomposing ash trees

• Migratory and resident birds and mammals

• Rare plants and animal species

During the data collection phase, it became apparent that gaps in some of the existing data

recommendations for addressing all of the

secondary purpose of this report is to identify

preliminary restoration strategies and permit

SUMMARY OF FINDINGS

dependent upon site hydrology consisting of

condition, but these systems are too complex to

•

good information on understanding

conclusions that can be translated

•

historic drainage patterns of the

• In response to these changes, ditches


•

•

locations, the surface drainage patterns

•

implementation of restoration measures

• killed all the mature ash trees including


FLATWOODS WIDE RESTORATION STRATEGIES

•

• Restore surface drainage patterns to

patterns are restored across these

•

•

Canal in its entirety to restore historic

•

Under certain conditions, ditches may

• topography and surface hydrology at the abandoned golf course and picnic area

•

• Establish a tree planting program using Belle Isle genotypes to replace lost

are the dominant species and are

•

• All future utilities should be constructed


HISTORIC FLATWOODS

CELL 7HISTORIC FLATWOODS

CELL 6A CELL 6B

CELL 5

CELL 4

CELL 3

CELL 8

CELL 1B

CELL 1A

HISTORIC FLATWOODS

CELL 2A

CELL 2B

Figure 13. Flatwoods Divisions

FLATWOODS ENLARGEMENTS – ANALYSIS AND RECOMMENDATIONS

in shaping the current characteristic of the

location to the other and a closer analysis of

It should be noted that recommendations

more detailed analysis under the next phase of

detailed topographic, bathymetric and large


CELL 1 ANALYSISbecome mostly dry as one might expect of a

represents one of the most degraded areas in

is bisected by numerous foot paths and the

hydrology, causing large areas to remain

Phragmites australisin this area has been mostly successful but

Cell 1A Restoration Strategies:

•

•


Figure 14. Flatwoods Division - Cells 1A &1B

HISTORIC TRAIL

DITCH

EXISTING STANDING WATER/V

EXPANDED STANDING WATER

TREELINE

TREES UNDER STRESS

EXISTING OVERLAND FLOW

CULVERT/PIPE

SUSPECTED CULVERT

EXISTING FILL/DRAINAGE BA

PROPOSED SURFACE WATERCONNECTIVITY

LEGEND

?

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VEVEVEVEEEVEVVEVVEVEVEEVEEEVEEEVEERNRRRRRRRRRRRRRRRRR AL POOL

R///R/////R///R//////R////////////////VERNRNNRNRNRNRRRRNRNRRRRNNNNRNNRNRRRNRRNRNNRRNNRNRRRRRRRRRNNNAL POOOOOOOOOOOOOOOOOOLLLLLLLLLLLLLLLLLLLLLLLLLLLLLL

RRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRIRIRIRIRIRIRIRIRRRRIRIRIR EREEREREREREREREREERERRERERERRREEERERR

CELL 3

CELL 8

CELL 1B

CELL 1A

CELL 2A

CELL 2B

HISTORIC FLATWOODS

LEVEL 1 DITCH & OUTLET

(HIGH QUALITY)

MINOR OBSTRUCTION

(EXTREMELY WET)W

ILD

WO

OD

PA

SS

N

OAKWAY TR

AIL

NATIVE ZOO

?


• grades to match existing adjacent

•

in a strategic location, creating surface

•

Cell 1B Restoration Strategies:

•

• A decision needs to be made about

is intended to expand herpetofauna

as an emergent habitat and introduce

• restore grades to match existing

•

•

•


CELL 2 ANALYSIS

diameter oak trees still exist but the understory

the abandoned buildings, tee boxes and by

is fenced off and is seldom used by park staff,

length of time and is considered a stable system

contains prolonged inundation and has caused

in this location indicating that if this excess

reduced to a small perennial pool adjacent to

a single location directly behind the abandoned

the drain pipe extends, but it appears to be

cattail pond exists and is discharging additional


CELL 3

CELL 1B

CELL 1A

CELL 2A

CELL 2B

REMOVE PIPE & PLUG LEVEL 3 OUTLET

RESTORE UNDERSTORY

HIGH QUALITYHERPS HABITAT

GOLF COURSE

FILL

WILDW

OOD

PASS

EXISTING DRAIN SWALE

EXISTING CHAIN LINK FENCE TO BE REMOVED

RESTOREHISTORIC WETLANDS

HISTORIC TRAIL

DITCH

EXISTING STANDING WATER/VERRNAL POOL

EXPANDED STANDING WATER/VEERNAL POOOLLL

TREELINE

TREES UNDER STRESS


CULVERT/PIPE

SUSPECTED CULVERT

EXISTING FILL/DRAINAGE BARRIER


LEGEND

?

N

Figure 15. Flatwoods Division - Cells 2A &2B


Phalaris arundinacea

Lonicera maackiito the absence of historic hydrology that may


•

• Maintain herpetofauna habitat in pool in

•

•


•

• the outer edge of the tree canopy that

•

• Consider the restoration of the golf

Lake Muskoday by dispersing the cell

•

•

• Install a second relief point for Cell 2B to the golf course to accommodate the


CELL 3 ANALYSIS

occupied by Lake Muskoday and the abandoned

greatest impact on cell hydrology and extends

are drained by the primary ditch and through

except for a small area in the southeast corner

healthy except for a small cluster of maples in the southeast corner of the site that is attributed

trees is clearly noticeable especially along the

Phalaris arundinacea

Lonicera maackiiin this location due to the absence of historic

canal except at the ditch outlets, and existing

•

•

• Fill all ditches, plug all outlets to the canal and maintain a land bridge along

•

•


CELL 3

CELL 2B

CELL 5

CELL 8

WILD

WO

OD

PASS

PLUG LEVEL 1 OUTLET

MAINTAIN BERM ALONG CANAL

TEST PIT

REMOVE PIPES & PLUG LEVEL 2 OUTLETS

REMOVE PIPES & PLUG LEVEL 3 OUTLETS

N

HP

Figure 16. Flatwoods Division - Cells 3

HISTORIC TRAIL

DITCH

EXISTING STANDING WATER/VERNAL PPPOOOOOOOLLL

EXPANDED STANDING WATER/VERNAALLL PPPOOOOOOOLLL

TREELINE

TREES UNDER STRESS


CULVERT/PIPE

SUSPECTED CULVERT

EXISTING FILL/DRAINAGE BARRIEREXISTING FILL/DRAINAGE BARRIER


LEGEND

?


CELL 4 ANALYSIS

this area is unlikely due to its current use and

occupied by Lake Muskoday and the abandoned

• of the large diameter trees that occurred

• natural drainage patterns to the historic

•

•

• parking lot occupies a strategic corner of

the natural understory is absent and maintained

Cell 4 Restoration Strategies:

•

Consider restoration of the abandoned golf course to historic

Station parking lot and restore to

Implement replanting program using


HISTORIC TRAIL

DITCH

EXISTING STANDING WATER/VERN

EXPANDED STANDING WATER/VER

TREELINE

TREES UNDER STRESS


CULVERT/PIPE

SUSPECTED CULVERT

EXISTING FILL/DRAINAGE BARRIER


PROPOSED BERM

LEGEND

?

NAL POOL

RNAL POOOLLLLLLLLLLLLLLL

RRRRRRRRRRRRRRRRRRRRRRRRRRRR

CELL 5

CELL 3

CELL 2B

CELL 4

CONSTRUCT BERMTO BLOCK FLOW

REPLANT WITH TREES

RESTORE HISTORIC WETLANDS

REMOVE FENCE

REMOVE FENCE

PORTA

GE W

AY

RESTORE UNDERSTORY VEGETATION

REMOVE PARKING LOT

N

CONSTRUCT BERMTO BLOCK FLOW

REMOVE BRIDGE

Figure 17. Flatwoods Division - Cell 4


CELL 5 ANALYSIS

and saturated soils indicate that good pool

established indicating that the duration of the

Across the cell, tree conditions appear mostly

the ponding has been occurring for a number

the other cells, the loss of ash trees are clearly

trees and dense honeysuckle is extremely



N

HISTORIC TRAIL

DITCH

EXISTING STANDING WATER/VERNAL POOOOLLL

EXPANDED STANDING WATER/VERNAL POOOOOOLL

TREELINE

TREES UNDER STRESS


CULVERT/PIPE

LEGEND?

NO FLOW OBSERVED

CULVERT PIPE NOT FOUND

CELL 5

CELL 6BCELL 6

EXCESSIVE HYDROLOGY

REMOVE ROAD

NO HYDROLOGY

REMOVE PIPE & PLUG LEVEL OUTLET

CELL 6

REMOVE BRIDGE

*

MAINTAIN BERM ALONG CANAL

TEST PIT

RESTORE


NO FLOW OBSERVED

NO FLOW OBSERVED

CELL 3

CELL 8

Cell 5 Restoration Strategies:

•

•

•

•

• Restore the portion of the Safari Zoo

canal crossings and fencing, Safari Zoo

and restore historical grades to direct

•


CELL 6 ANALYSISthese three pools appeared to be larger and

closed Safari Zoo and is described under Cell

Honeysuckle is abundant throughout this cell

a barrier that blocks the migration of surface

the center of this cell, a cluster of red oaks are


Figure 19. Flatwoods Division - Cell 6A & 6BFiguuuuurerrrrrrrrrrrrrrr 111111111111111111111119.9.99999999999999999999..999.. FlFFFFFFFFFFFFFFFFFF atwowoodds s sss ss sss sss sss DiDiiDiDiDiDiDiDiDiDDDiDDiDDDDDDDDDDDiDDDDDiDDDDDDiivivvvviiviivvvivivivivvvvvvvvvvvvvvvvviiiisssiiisisisssssss on ---------- Cell 6AAAAAAAAAAAAAAAAAA &&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&& 66666666666666666666666BBBBBBBBBBBBBBBBB

CELL 5

CELL 8

CELL 6B

CELL 6A

TEST PIT

PROPOSED WATER CONTROL

STRUCTURE

TEST PIT

EXISTING SURFACE FLOW TO CANAL

DEAD OAKTREES

N

HISTORIC TRAIL

DITCH

EXISTING STANDING WATER/VERNAL POOOOOLL


TREELINE

TREES UNDER STRESS


CULVERT/PIPE

LEGEND?


STRUCTURE

??

LOCATION OF PROPOSED STOP LOG STRUCTURE

REMOVE ALL PIPE & PLUG OUTLETS

ALONG CANAL


One note of interest is that the resident


• Consider relocating the proposed stoplog structure form the east end of

• berm along the bank trapping additional

•

•

•



•

•

•

•


CELL 7 ANALYSIS

parallels the entire length of this cell connecting

constructed on grade and could not be located

that these structures historically extended

of oak trees on the eastern end of the cell are


•


•

•

• In up to three locations to be

restore historical drainage patterns to

• Consider restoration of this cell to

restoration around the perimeter of this

•

•



CELL 8

CELL 7

CELL 6B

THE STRAND

RESTORE FLATWOODS

UNDERSTORY


STRUCTURE

MOWED FIELD/ HISTORIC FLATWOODS

RESTORE FLATWOODS UNDERSTORY

REMOVE FILL

N

HISTORIC TRAIL

DITCH

EXISTING STANDING WATER/VERNAL POOOOLL


TREELINE

TREES UNDER STRESS


CULVERT/PIPE

LEGEND?

REMOVE PIPE & PLUG OUTLETS


CELL 8 ANALYSIS

from the hydrologic connection to the cell due to

corner of the cell and discharges into Lake

a secondary purpose of the braided ditching

plans for Lake Okonoka identify this outlet as

the cell, ditching impacts are less apparent, and

ground and partially block the main ditch that

of an impact due primarily to the blockage of

extend to the edge of the asphalt path and

most pool is the deepest and by late summer, is

root collars on the large oak trees suggest a

to fallen ash trees, blockages in the ditching system, abandoned picnic facilities and

grades on both sides, drains to this strip of

trees in this area is clearly noticeable creating

small trees are taking hold in response to the additional light penetrating to the ground


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CELL 1B

CELL 8

CELL 6B

CELL 7

PICNIC GROVE

RESTORE FLATWOODS EDGE

REMOVE WOODSIDE DRIVE & RESTORE HISTORIC FLOW

REMOVE PIPE & PLUG LEVEL 3

OUTLET

HISTORIC EDGE

RESTORE FLATWOODS EDGE

PROPOSE WATER CONTROL

STRUCTURE IN LEVEL 2 OUTLET

N

HISTORIC TRAIL

DITCH

EXISTING STANDING WATER/VERNAL POOOOLL


TREELINE

TREES UNDER STRESS


CULVERT/PIPE

LEGEND

?

REMOVE PIPE & PLUG LEVEL 1

OUTLET


•

recommendations for decisions on the

•

important for restoring historic drainage

•

• as part of the Habitat Restoration project

•

•

•

• picnic structures on the north edge of

SUMMARY OF FINDINGS

protecting the large diameter trees, is the competing recreational uses and demands

and trails, roads and their associated cut and

this report attempts to do this, it is presented


• A greater understanding on the

include additional and more precise

•

NEXT STEPS

• Resolution of locations and cross sections of trails, roads and parking to

•

currently not part of this initial study

continued monitoring of pool hydrology effecting the health of large diameter


4 | BIBLIOGRAPHY

Belle Isle Canal Rehabilitation; Johnson Johnson

Lake Okonoka And South Shore Habitat

Lake Okonoka Habitat Restoration; Herpetological Monitoring Report; Herpetological Resources and Management,

Lake Okonoka Habitat Restoration in the Detroit

Okonoka Habitat Restoration Design;

60 | Bibliography

prepared by: prepared for · 2016. 11. 17. · belle isle projects uhvwrudwlyh ehqhÀwv wr wkh...

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