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

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

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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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A

B

CMONTGOMERY

VILLAGE AVENUE

FLOW

I-270ROUTE

355

ROUTE118

ROUTE355 WATKINS

MILL ROAD

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

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It was alarming to see how close 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.

DISCOVERING FLOODPLAINS AT CAPACITY

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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:

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

ROUTE 28

DAWSONVILLEGAUGE

Elevation 308 ft

DRY SENECA CREEK

LITTLE SENECA CREEK

GREAT SENECA CREEK

MT. LEBANON DAMASCUS

Elevation

787 ft

POOLESVILLEElevation

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

STREAM FLOW

CONTROLED RELEASE

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• Readings represent similar characteristics of the flood volume shown in Exhibit photographs, taken from Watkins Mill Road bridges.

• Historical data is available– USGS has been monitoring the gauge for over 80 years, gives good baseline comparisons

• The researched data from this flood gauge is used in this chart. – The next charts show just how extreme flood volume has been.

• The data shows a trend of extremely high levels of peak flooding (in cubic feet per second)

– Backed  by  ‘Five  Annual  Peak  Flood  (CFS)  Readings’  from  the  Gauge’s  historic  record,  and  readings  for the two photography dates,.

WHY USE THE DAWSONVILLE GAUGE FLOOD DATA?

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

Discharge considered At flood stage is2,500 (CFS)

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

120 (CFS) AVERAGE

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The last years have shown a dramatic increase in peak flood volume, which does not correlate to annual precipitation changes.

This effect may be better correlated to land use changes in the watershed area.

Larger and larger floods may be anticipated if more buffering area is removed.

Historical precipitation data: NOAA (noaa.gov)

2930

2150

2890

7600

8280

1167.384883.412

1191.006824.23

1123.696

2009 2010 2011 2012 2013

PEAK FLOOD VOLUME AND PRECIPITATION

VOLUME PRECIP MM

Peak Flood Volume Data Shows the Beginning of a Trend

Cubi

c Ft P

er S

econ

d

0

1000

2000

3000

4000

5000

6000

7000

8000

28-A

pr

29-A

pr

30-A

pr

1-M

ay

2-M

ay

3-M

ay

4-M

ay

5-M

ay

6-M

ay

7-M

ay

8-M

ay

9-M

ay

10-M

ay

11-M

ay

12-M

ay

13-M

ay

14-M

ay

15-M

ay

16-M

ay

17-M

ay

18-M

ay

19-M

ay

20-M

ay

21-M

ay

22-M

ay

23-M

ay

24-M

ay

25-M

ay

26-M

ay

27-M

ay

28-M

ay

29-M

ay

MAX ft3/sec

6,220APRIL 30,

2014

7,040 MAY 16,

2014

COMPARED TO FLOOD VOLUME IN THIS EXHIBIT

Discharge considered

at flood stage is

2,500 (CFS)

2014 Data Establishes this Increase in Flood Volume as a Statistical Trend

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ROUTE 355

WATKINS MILL

ROAD

PROPOSED M-83 ROUTE

A

B

CGREAT SENECASTREAMVALLEY

PARK

ROUTE 118

I-270 &FUTURE EXIT 12

SouthValley ParkBlohm

Park

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

BRIDGE “A”                                                                                                                                                            

STREAM FLOW

GREATSENECACREEK LAKE

WHETSTONE

WHETSTONE RUN

WALKERS RUN

MONTGOMERY VILLAGE AVENUE

M-83WATKINS

MILL ROAD

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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

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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.

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

April 30, 2014

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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.

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

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

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.

APRIL 30, 2014

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

Peak storm water spreading across floodplain where trees, grasses &

vegetation filter sediment.

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

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

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 19

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

BRIDGE “B”

MONTGOMERY VILLAGE GOLF COURSE

CABIN BRANCH STREAM

GREATSENECA CREEK

WATKINS MILL ROAD

WHERE M-83 IMPACTS

FLOODPLAINS

STREAM FLOW

GREATSENECASTREAMVALLEYPARK

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Two Geese and a Heron enjoy the flooded landscape

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

Composite ImageApril 30, 2014

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

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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”  

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

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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

GREAT SENECA CREEK

ROUTE 118

WATKINS MILL

ROAD

VIEWS  OF  BRIDGE  “C”  DURING  SECOND  FLOOD  EVENT

These pictures show flood event at capacity below the confluence of Great Seneca Creek and North Creek. Also shows the accumulative affect of storm watermoving down Great Seneca Creek that started near Damascus at Mt. Lebanon. 24

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

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

M-83 IMPACT ON NORTH GERMANTOWN GREENWAY PARK

STREAMFLOW

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REMOVING M-83 IS THE SOLUTION

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

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

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

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• 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