m83 flood plain impact

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1 Data & Photographs Present Compelling Evidence to Support the Removal of “Proposed M- 83 Extended” from the Master Plan of Highways & Transitways for Montgomery County, MD ANN SMITH: Author, Biologist & Photographer EDNA MILLER: Editor & Graphic Artist TAME COALITION: Sponsor AN EXHIBIT TO REMOVE PROPOSED M-83 EXTENDED tamecoalition.blogs pot.com

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Page 1: M83 Flood Plain Impact

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Data & Photographs Present Compelling Evidence to Support the Removal of “Proposed M-83 Extended”

from the Master Plan of Highways & Transitways for Montgomery County, MD

ANN SMITH: Author, Biologist & PhotographerEDNA MILLER: Editor & Graphic Artist

TAME COALITION: Sponsor

AN EXHIBIT TO REMOVE PROPOSED M-83 EXTENDED

tamecoalition.blogspot.com

Page 2: M83 Flood Plain Impact

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This exhibit focuses on the floodplains in Great Seneca Stream Valley Park & North Germantown Greenway Park. Floodplain benefits revealed during peak flood events are captured on April 30 & May 16, 2014. Maps show where proposed M-83 Master Plan Alignment would impact multiple floodplain areas within Great Seneca Creek Watershed. To construct M-83 through these forested ecosystems would accelerate peak storm water discharge downstream.

TAME Coalition is raising public awareness about the destructive environmental impacts of proposed Mid-County Highway Extended

Page 3: M83 Flood Plain Impact

In this “Exhibit To Remove M-83 Extended”

• GOOGLE MAPS LOCATE: – Site of each peak flood event photographed from three Watkins Mill Road bridges

over tributaries of Great Seneca Creek.– Route proposed for M-83 Extended through the length of Great Seneca Stream Valley

Park & across North Germantown Greenway Park. – The proximity of Dawsonville Gauge at the confluence of Little Seneca Creek with

Great Seneca Creek as comparable with the elevation drop (gradient) of Exhibit sites marked bridges “A”, “B” & “C”.

• PHOTOGRAPHS SHOW: compelling examples of peak flood water spreading across floodplains, which slows down velocity and drops sediment.

• CHARTS CONNECT: Dates from the Dawsonville Gauge readings in cubic feet per second (CFS) align with this Exhibit’s photography dates.

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Page 4: M83 Flood Plain Impact

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A

B

CMONTGOMERY

VILLAGE AVENUE

FLOW

I-270

ROUTE 355

ROUTE 118

ROUTE355 WATKINS

MILL ROAD

N. GERMANTOWN GREENWAY PARK

GREATSENECASTREAMVALLEY

PARK

M-83 IMPACTS FLOODPLAINS

The floodplain degradation and deforestation of building M-83 would cause increased storm water runoff surges in the following tributaries:1) Dayspring Creek runs through North

Germantown Greenway Park2) Wildcat Branch converges with Great Seneca

Creek above Brink Road 3) Brandermill Run enters Great Seneca west of

Bridge “C”4) Cabin Branch Stream enters Great Seneca

west of Bridge “B” 5) Whetstone Run enters Great Seneca west of

Bridge “A”6) Walkers Run enters Whetstone Run southeast

of Bridge “A” Proposed M-83 would NOT reduce sediment loads into the Potomac River & Chesapeake Bay.

INTRODUCTION TO IMPACTED FLOODPLAINS OF GREAT SENECA CREEK & ITS TRIBUTARIES IF M-83 EXTENDED IS CONSTRUCTED

Page 5: M83 Flood Plain Impact

It was alarming to see how close raging floodwaters came up to this Watkins Mill Road bridge, over a tributary of Great Seneca Creek.

Great Seneca Creek starts at Mount Lebanon in Damascus, (787 Ft. Elevation), runs through this mid-point location along Watkins Mill Road & ends at the Potomac. 5

DISCOVERING FLOODPLAINS AT CAPACITY

Page 6: M83 Flood Plain Impact

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1. ELEVATIONS ABOVE SEA LEVEL: For Great Seneca Creek & its tributaries gradient; elevations explain the levels flood waters must drop from Damascus to Montgomery Village, then to Dawsonville.

2. WATKINS MILL ROAD: Although a distance from the Dawsonville Gauge (CFS Data Source), peak flood volume shown by its gradient is comparable to the Gauge’s readings on the matching dates in the Exhibit.

3. PROPOSED M-83 EXTENDED ROUTE: Is perpendicular to tributary flood-plains near Watkins Mill Road bridges, runs parallel through Great Seneca Stream Valley Park & perpendicular to North Germantown Greenway Park.

4. GREAT SENECA CREEK FLOODPLAINS & TRIBUTARIES: M-83 would degrade multiple floodplains’ ability to slow down peak flood events. M-83 would accelerate peak flood velocity, which would carry greater amounts of sedimentary load downstream.

Google Maps Used In This Exhibit Identify:

Page 7: M83 Flood Plain Impact

Elevations from Damascus to “Proposed M-83” represent a larger gradient drop than those leading from Montgomery Village to the Dawsonville Gauge

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ROUTE 28

DAWSONVILLEGAUGE

Elevation 308 ft

DRY SENECA CREEK

LITTLE SENECA CREEK

GREAT SENECA CREEK

MT. LEBANON DAMASCUS

Elevation

787 ft

POOLESVILLE Elevation

413 ft

BOYDSElevation

559 ft

MONTGOMERY VILLAGE Elevation

317 ft

GERMANTOWN Elevation

550 ft

FUTURE EXIT 12

GREATSENECA STREAMVALLEY

PARKWATKINS

MILL ROAD

PROPOSED M-83

ROUTE

N. GERMANTOWN

GREENWAY PARK

STREAM FLOW

CONTROLED RELEASE

Page 8: M83 Flood Plain Impact

These readings represent similar characteristics of the flood volume shown in Exhibit photographs, taken from Watkins Mill Road bridges. USGS has been monitoring the gauge for over 80 years.

The researched data from this flood gauge is used in this chart. The next chart shows just how extreme flood volume has been.

With ‘Five Annual Peak Flood (CFS) Readings’ from the Gauge’s historic record, and readings for the two photography dates, the chart shows a trend of extremely high levels of peak flooding in cubic feet per second.

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WHY USE THE DAWSONVILLE GAUGE FLOOD DATA?

Page 9: M83 Flood Plain Impact

USGS DISCHARGE READINGS FROM DAWSONVILLE GAUGE ALIGN WITH PHOTOGRAPHS TAKEN IN THIS EXHIBIT

Discharge considered At flood stage is

2,500 (CFS)

6,220 (CFS) 7,040 (CFS)

120 (CFS) AVERAGE

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Page 10: M83 Flood Plain Impact

Cubi

c Ft

Per

Sec

ond

20092930

20102150

20112890

2012

76002013

8280FIVE YEARS OF PEAK FLOOD

READINGS

0

1000

2000

3000

4000

5000

6000

7000

8000

Series2

6,220 APRIL 30,

2014

7,040 MAY 16,

2014

COMPARED TO FLOOD VOLUME IN THIS EXHIBIT

Discharge considered

at flood stage is

2,500 (CFS)

A TREND IN ANNUAL PEAK FLOOD VOLUME

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Page 11: M83 Flood Plain Impact

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EXHIBIT OF

PHOTORAPHS

TAKEN FROM:

“A” – Whetstone Run bridge

“B” - Cabin Branch bridge

“C” – Great Seneca bridgeROUTE

355

WATKINS MILL

ROAD

PROPOSED M-83 ROUTE

A

B

CGREAT SENECASTREAMVALLEY

PARK

N. GERMANTOWN

GREENWAY PARK

ROUTE 118

I-270 &FUTURE EXIT 12

South Valley ParkBlohm

Park

Page 12: M83 Flood Plain Impact

A CLOSE-UP FROM BRIDGE “A” – WHERE STORM WATER FLOWS ACROSS FLOODPLAINS IN RELATION TO M-83 ROUTE

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BRIDGE “A”

STREAM FLOW

WHERE M-83

IMPACTS

FLOODPLAIN

GREATSENECACREEK LAKE

WHETSTONE

WHETSTONE RUN

WALKERS RUN

MONTGOMERY VILLAGE AVENUE

M-83

WATKINS MILL ROAD

Smith
Page 13: M83 Flood Plain Impact

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An example of a stream’s capacity inside the banks of a snake curve showing a natural meander that slows water and drops sediment.

VIEW FROM BRIDGE “A” – CAPTURED AT WHETSTONE RUN & BLOHM PARK

Page 14: M83 Flood Plain Impact

Water flows West across the floodplain to spread out, slow down & drop sediment.

Evidence of how vegetation and trees naturally absorb water above banks of Run.

M-83 SITE IS TO THE

RIGHT

M-83 SITE IN VIEW

VIEW FROM BRIDGE “A” – AT WHETSTONE RUN IN FLOOD

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April 30, 2014

Page 15: M83 Flood Plain Impact

Example of sediment & debris that settled after a flood at the Blohm Park, showing the efficiency of trees, shrubbery and grasses to relieve storm water of its load.

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VIEWED FROM BRIDGE “A” – AT WHETSTONE RUN & BLOHM PARK

M-83 PROPOSED DOWN THE CENTER

Page 16: M83 Flood Plain Impact

VIEW WEST OF BRIDGE “A” – FLOOD CAPTURED AT WHETSTONE RUN FROM THE GAZEBO AT BLOHM PARK

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Current overflow from Lake Whetstone into Whetstone & Walkers Run crosses the forested floodplain of proposed M-83 Extended Route. Its culverts and pavement would eliminate this floodplain benefit.

LOCATION OF PROPOSED

M-83

SITE OF PROPOSED

M-83

APRIL 30, 2014

Page 17: M83 Flood Plain Impact

Flood reaches ‘South Valley Park Ball Field’ in Montgomery Village

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FLOOD IS MOVING TOWARDS

BRIDGE

Peak storm water spreading across floodplain where trees, grasses &

vegetation filter sediment.

Watkins Mill Elementary

School

VIEW IS EAST OF BRIDGE “A” – CAPTURED DURING THE SECOND FLOOD EVENT

Page 18: M83 Flood Plain Impact

THE HISTORY OF BRIDGE “A” – WHETSTONE/WALKERS RUN NEAR WATKINS MILL ELEMENTARY SCHOOL

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This 1997 bridge design was based on the County Council’s 1992 decision not to include the

proposed M-83 . Six people were almost swept away in 1987 by the swift current at Whetstone Run in Montgomery Village, Maryland.

PICTURE SUBMITTED BY JANE WILDER

Page 19: M83 Flood Plain Impact

MAP SHOWS BRIDGE “B” – WATER FLOW OF CABIN BRANCH & GREAT SENECA CREEK Cabin Branch Stream flowing across Montgomery Village Golf Course

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BRIDGE “B”

MONTGOMERY VILLAGE GOLF COURSE

CABIN BRANCH STREAM

GREATSENECA CREEK

WATKINS MILL ROAD

WHERE M-83 IMPACTS

FLOODPLAINS

STREAM FLOW

GREATSENECASTREAMVALLEYPARK

Page 20: M83 Flood Plain Impact

Two Geese and a Heron enjoy the flooded landscape

20High levels of flood waters cross floodplain, as water spreads out sediment drops.

APRIL 30, 2014

ADJACENT TO BRIDGE “B” – VIEWS OF MONTGOMERY VILLAGE GOLF COURSE

Page 21: M83 Flood Plain Impact

NEAR BRIDGE “B” – SHOWS THE SAME VIEW OF CABIN BRANCH TRIBUTARY “At Flood” and “Dry” across floodplain, taken from the same hill near bridge “B”

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AT FLOOD ON APRIL 30, 2014(6,220 CFS) DRY ON AUGUST 7, 2014

Page 22: M83 Flood Plain Impact

LOCATION OF BRIDGE “C” COMPARED TO PROPOSED M-83 ROUTEAfter the confluence of Dayspring Creek and Great Seneca Creek

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BRIDGE “C”

GREAT SENECA CREEK

NORTH CREEK

GREAT SENECA STREAMVALLEY PARK

BRANDERMILLRUN

WHERE M-83 IMPACTS

FLOODPLAIN STREAM FLOW

DAYSPRING

CREEK

GREAT SENECA CREEK

ROUTE 118

WATKINS MILL

ROAD

Page 23: M83 Flood Plain Impact

VIEWS OF BRIDGE “C” DURING SECOND FLOOD EVENT

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These pictures show flood event at capacity below the confluence of Great Seneca Creek and North Creek. Also shows the accumulative affect of storm water moving down Great Seneca Creek that started near Damascus at Mt. Lebanon.

FLOOD MOVING WEST TOWARD

M-83

WATKINS MILL ROAD

Page 24: M83 Flood Plain Impact

Second Flood Event on May 16, 2014 August 7, 2014

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Note the height of the fenced-in boxes.They are part of WMET Radio Towers located at Great Seneca Creek bridge “C”.

IN FLOOD

VIEWS NEAR BRIDGE “C” – PICTURES TAKEN FROM HILL OVERLOOKING THE FLOODPLAIN

DRY

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If proposed M-83 were built through North Germantown Greenway Park, it would clear cut the interior forest & accelerate flood waters beyond capacity to bridge “C” site.

WILDCAT BRANCH

NORTHGERMANTOWN

GREENWAY PARK

BRIDGE “C”

BRINK ROAD

GREAT SENECACREEK

WATKINS MILL ROAD

DAYSPRING CREEK

WHERE M-83

IMPACTS

FLOODPLAIN

M-83

M-83 IMPACT ON NORTH GERMANTOWN GREENWAY PARK

STREAMFLOW

Page 26: M83 Flood Plain Impact

REMOVING M-83 IS THE SOLUTION

• Without the full support of these existing forested floodplains, critical conditions for stream flow and sedimentary load downstream could only increase.

• M-83 development will not benefit Maryland’s measureable goal of reducing sediment load in the Great Seneca Creek Watershed.

• To remove Mid-County Highway Extended (M-83) from the Master Plan of Highways & Transitways would ensure forested floodplains continue their function.

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Page 27: M83 Flood Plain Impact

RESOURCES

TECHNICAL READINGS FOR THIS POWER POINT PRESENTATION:

• State Law: ww.mde.state.md.us/Seneca_Sed_TMDL_093011_Final.pdf • EPA: www.epa.gov/Seneca Creek Sediment TMDL_combo.pdf

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ACKNOWLEDGEMENT OF THANKS TO TAME COALITION TEAM VOLUNTEERS:Margaret Schoap, Richard & Jane Wilder,

Bing Garthright & Patty King, Lauren & Dale Smith