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M83 Flood Plain Impact
- 1. 1 AN EXHIBITTO REMOVE PROPOSED M-83 EXTENDED 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 tamecoalition.blogspot.com
- 2. 2 TAME Coalitionis raising public awareness about the destructive environmental impacts of proposed Mid-County Highway Extended 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.
- 3. In this “ExhibitTo 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. 3
- 4. 4 A B C MONTGOMERY VILLAGE AVENUE FLOW I-270 ROUTE 355 ROUTE 118 ROUTE 355 WATKINS MILL ROAD GREAT SENECA STREAM VALLEY 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 Park 2) 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
- 5. DISCOVERING FLOODPLAINS ATCAPACITY 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
- 6. 6 Google MapsUsed In This Exhibit Identify: 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.
- 7. Elevations from Damascusto “Proposed M-83” represent a larger gradient drop than those leading from Montgomery Village to the Dawsonville Gauge 7 DRY SENECA CREEK ROUTE 28 DAWSONVILLE GAUGE Elevation 308 ft LITTLE SENECA CREEK GREAT SENECA CREEK MT. LEBANON DAMASCUS Elevation 787 ft POOLESVILLE Elevation 413 ft BOYDS Elevation 559 ft MONTGOMERY VILLAGE Elevation 317 ft GERMANTOWN Elevation 550 ft GREAT SENECA STREAM VALLEY PARK FUTURE EXIT 12 WATKINS MILL ROAD PROPOSED M-83 ROUTE STREAM FLOW CONTROLED RELEASE
- 8. These readings representsimilar 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. 8 WHY USE THE DAWSONVILLE GAUGE FLOOD DATA?
- 9. USGS DISCHARGE READINGSFROM 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 9
- 10. 2013 8280 FIVEYEARS Cubic Ft Per Second 2009 2930 2010 2150 2011 2890 2012 7600 OF PEAK FLOOD READINGS 8000 7000 6000 5000 4000 3000 2000 1000 0 28-Apr 29-Apr 30-Apr 1-May 2-May 3-May 4-May 5-May 6-May 7-May 8-May 9-May MAX ft3/sec 10-… 11-… 12-… 13-… 14-… 15-… 16-… 17-… 18-… 19-… 20-… 21-… 22-… 23-… 24-… 25-… 26-… 27-… 28-… 29-… 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 10
- 11. 11 ROUTE 355 WATKINS MILL ROAD PROPOSED M-83 ROUTE A B C GREAT SENECA STREAM VALLEY PARK ROUTE 118 I-270 & FUTURE EXIT 12 South Blohm Valley Park Park
- 12. A CLOSE-UP FROMBRIDGE “A” – WHERE STORM WATER FLOWS ACROSS FLOODPLAINS IN RELATION TO M-83 ROUTE 12 GREAT SENECA CREEK LAKE BRIDGE “A” MONTGOMERY VILLAGE AVENUE STREAM FLOW WHETSTONE WHETSTONE RUN WALKERS RUN M-83 WATKINS MILL ROAD
- 13. 13 VIEW FROMBRIDGE “A” – CAPTURED AT WHETSTONE RUN & BLOHM PARK An example of a stream’s capacity inside the banks of a snake curve showing a natural meander that slows water and drops sediment.
- 14. VIEW FROM BRIDGE“A” – AT WHETSTONE RUN IN FLOOD 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. 14 April 30, 2014
- 15. 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. 15 VIEWED FROM BRIDGE “A” – AT WHETSTONE RUN & BLOHM PARK
- 16. VIEW WEST OFBRIDGE “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. 16 APRIL 30, 2014
- 17. VIEW IS EASTOF BRIDGE “A” – CAPTURED DURING THE SECOND FLOOD EVENT Flood reaches ‘South Valley Park Ball Field’ in Montgomery Village 17 Peak storm water spreading across floodplain where trees, grasses & vegetation filter sediment.
- 18. THE HISTORY OFBRIDGE “A” – WHETSTONE/WALKERS RUN NEAR WATKINS MILL ELEMENTARY SCHOOL 18 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 CREEK Cabin Branch Stream flowing across Montgomery Village Golf Course 19 WATKINS MILL ROAD BRIDGE “B” MONTGOMERY VILLAGE GOLF COURSE GREAT SENECA CREEK CABIN BRANCH STREAM WHERE M-83 IMPACTS FLOODPLAINS STREAM FLOW GREAT SENECA STREAM VALLEY PARK
- 20. ADJACENT TO BRIDGE“B” – VIEWS OF MONTGOMERY VILLAGE GOLF COURSE Two Geese and a Heron enjoy the flooded landscape 20 APRIL 30, 2014 High levels of flood waters cross floodplain, as water spreads out sediment drops.
- 21. 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” 21 AT FLOOD ON APRIL 30, 2014 (6,220 CFS) DRY ON AUGUST 7, 2014
- 22. LOCATION OF BRIDGE“C” COMPARED TO PROPOSED M-83 ROUTE After the confluence of Dayspring Creek and Great Seneca Creek 22 WHERE M-83 IMPACTS FLOODPLAIN STREAM BRIDGE “C” GREAT SENECA CREEK NORTH CREEK GREAT SENECA STREAM VALLEY PARK BRANDERMILL RUN FLOW GREAT SENECA CREEK ROUTE 118 WATKINS MILL ROAD
- 23. VIEWS OF BRIDGE“C” DURING SECOND FLOOD EVENT 23 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.
- 24. VIEWS NEAR BRIDGE“C” – PICTURES TAKEN FROM HILL OVERLOOKING THE FLOODPLAIN Second Flood Event on May 16, 2014 August 7, 2014 24 Note the height of the fenced-in boxes. They are part of WMET Radio Towers located at Great Seneca Creek bridge “C”. IN FLOOD DRY
- 25. M-83 IMPACT ONNORTH GERMANTOWN GREENWAY PARK DAYSPRING CREEK 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. 25 WILDCAT BRANCH NORTH GERMANTOWN GREENWAY PARK BRIDGE “C” BRINK ROAD GREAT SENECA CREEK WATKINS MILL ROAD STREAM FLOW
- 26. REMOVING M-83 ISTHE 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. 26
- 27. • State Law:ww.mde.state.md.us/Seneca_Sed_TMDL_093011_Final.pdf • EPA: www.epa.gov/Seneca Creek Sediment TMDL_combo.pdf 27 ACKNOWLEDGEMENT OF THANKS TO TAME COALITION TEAM VOLUNTEERS: Margaret Schoap, Richard & Jane Wilder, Bing Garthright & Patty King, Lauren & Dale Smith
Editor's Notes
- #7 HIDE THIS SLIDE
- #8 These are the important details for you to see from the map 470 ft. Drop from Damascus to Montgomery Village,
- #9 Hidden Slide
- #12 Reiterate that these are the A,B,C Bridges from beginning slide. Upcoming Photographs Identify a “Working” Floodplain.
- #13 Talk about what I photographed. The road takes the wider girth. The impact is significant along this flood plain. A neighborhood is split in half
- #14 The good things about this watershed.
- #20 To the Left of picture the deforested hill will be an advantage for the highway because it is on top of the slope, but a disadvantage to the creek because the runoff will go directly into the creek. A wall will create a slump. Note 2:The Golf Course was recently bought by a developer. Increased runoff from new development will affect the current floodplain.
- #21 This is a second example of the Floodplain at work. Note the railing in both pictures.
- #23 Note That Dayspring Convergence is North of picture, and only Great Seneca Creek is shown. At this halfway point from Damascus, Dayspring, Wildcat Branch, Magruder Branch, and Goshen Branch have already merged. What we see is the smaller North Creek coming from East Village and Great Seneca From the North. Note 2: The M-83 running inside the wooded park and parallel to Great Seneca Creek will be dumping sediment into the water.
- #24 This is a tremendous amount of Clean Water
- #26 Note that Bridge C is at the bottom of this map, and we are looking at Several source streams. Also Note the Dayspring Silent Retreat Center is located in N. Germantown Greenway Park, and they have submitted 20 years of Invertebrate data showing a stream in good condition. Wildcat Branch is also in good invertebrate condition according to the state 2012 data.