New Germany Lake Sediments
New Germany Lake
Sediment Accumulation Survey
New Germany State Park
New Germany Lake Sediments
Purpose
• DNR has a dual mandate to protect our natural
resources and provide recreational use of the
lake at New Germany State Park
• Scientific collection of data establishes the
foundation for the development of a Lake
Management Plan
• Interests and concerns of park visitors and
neighbors are a vital component of the Plan –
Many thanks to the Friends of New Germany
for pursuing the issue and actively participating
in the process
New Germany Lake Sediments
Agenda
• Sediment Sampling (Cores)
– Collection and Analysis Procedures
– Historical Sediment
– Accumulated Sediment
• Sediment Chemistry and Pollutants
• Headwater Marsh Changes
• Sediment Nutrients
• Submerged Aquatic Vegetation Control
• Management Options
New Germany Lake Sediments
New Germany Lake Timeline
• Colonial Period – 9-15 foot channelized stream (Poplar Lick Run)
• 1837-1847 – Swauger Mill Dam was constructed at the same site as the
current dam. This created a lake of approximately 9 acres in size. The
dam was about 2 feet lower than the current dam.
• 1933-1935 – The current earthen dam with a concrete spillway was
constructed. This new dam impounded the existing ~13 acres.
• 2008 – DNR Engineering & Construction performed maintenance on
the concrete spillway, pedestrian bridge and drainage pipe.
• 2008 – DNR initiated the current study
New Germany Lake Sediments
Historical Markers of Sediment Levels
New Germany Lake Sediments
13
14
15
10
1112
Core Sample
Location Map
• Aerial Imagery is from 2007
• Yellow diamonds are location of cores
collected for this study
7A
78
9
6
21
3
5 4
• Core 16 was collected downstream to
identify/verify historical soil character
New Germany Lake Sediments
Core Collection Activities
New Germany Lake Sediments
Sediment Class Water
Sediment Type
Content
Soft Mud
65%
Sand-Silt-Clay
Lake Sediments
Firm Mud
53%
Silty-Clay
Comments
Sediment
Depth
Gassy; lots of
Organic material
Gassy; firm mud,
slightly sandy
0-0.4 Feet
0.4-1.8 Feet
Organic
Firm Mud
35%
23-32%
Sand-Silt-Clay
Silty Sand
Root structures;
slighty sandy mud
1.8-2.3 Feet
Firm mud, slightly
sandy
Historical Soil
Valley
Deposit
2.3-3.05 Feet
Alluvium
17%
gravelly muddy Sand
Soil Profile
10%
muddy sandy Gravel
Core #3 – South End of Lake Near Current Beach
Very firm; pebbles,
lots of rocks, color 3.05-3.7 Feet
change
Significant color
change, more red,
3.7-5.1 Feet
lots of ¾”rocks,
multiple large (1.5”)
rocks, very dry,
mottled
New Germany Lake Sediments
Lake Water Surface
13
14
15
10
-5 Feet
7A
78
9
-10 Feet
6
21
5 4
3
DAM
1112
New Germany Lake Sediments
Sediment Surface
13
14
15
-1.5 Feet
10
-3 Feet
7A
78
9
-4.5 Feet
6
21
-6 Feet
5 4
3
DAM
1112
New Germany Lake Sediments
Lead / Zinc Downcore Trends
Enrichment Factor based on Al
Zn
Pb
1.00
5.00
Core 9
0
1
Core 4
Zn
Enrichment Factor
Pb
2
3
4
5
0.00
2.00
3.00
4.00
0.00
0
30
4.00
5.00
6.00
1.0 Foot
1.0 Foot
Depth (cm)
20
40
50
60
1.0 Foot
Depth (cm)
60
Core depth (cm)
3.00
40
10
30
2.00
20
20
0
1.00
0
10
6
Zn
Pb
Core 11
Enrichment Factor based on Al
2.0 Feet
3.0 Feet
100
140
80
90
80
120
70
40
2.0 Feet
3.0 Feet
160
50
60
70
80
2.0 Feet
Lead and Zinc atmospheric and sediment
concentrations increased in the early 1900s due to
coal-powered factories, power generation, and the
automobile.
The increase of Lead and Zinc concentrations in the uppermost sediments imply
that the sediments shallower than 0.5-1 feet are more recent than 1900, and the
sediments deeper than 0.5-1 feet are older than 1900.
New Germany Lake Sediments
Total Sediment Accumulation within Current Shoreline
Section
Distance from Dam
[Feet]
Average Accumulated
Sediment [Feet]
South
0-410
2.65 [2.20-3.05]
Middle
410-1000
2.23 [1.84-3.01]
North
1000-1738
2.89 [1.84-3.81]
The average accumulated sediment thickness is 2.6 feet.
– 76% of all existing sediment in the lake was deposited in the
first 60+ years of the lake’s history (1840-1900)
– 24% of all existing sediment in the lake accumulated in the
last 108 years (1900-2008).
New Germany Lake Sediments
Chemical Analysis of Sediment
• 30 samples throughout the lake and at different
sediment depths were analyzed for their elemental
composition.
– No significant elemental enrichments were detected.
• Three Samples (Core #s 1,11,15) were analyzed for
semi-volatile organic pollutants and pesticides.
– No pesticides or semi-volatile organic pollutants were
detected.
New Germany Lake Sediments
• The Wetland is an Important Environmental Feature of New
Germany Lake.
– Sediment Trap
– Nutrient Sink
– Natural Habitat
New Germany Lake Sediments
Headwaters Marsh
Changes
• Aerial Imagery is from 2007
• Blue line is shoreline from 1946 USGS
Topographical Map
New Germany Lake Sediments
Headwaters Marsh Changes
Current Dam
Swauger Dam
Distances measured from multiple maps / images from the Marsh shoreline to Twin Oaks Road
Year
Document
Distance Measured (Meters)
1899
USGS Topo
330
1904
USGS Topo
342
1938
USGS Topo
349
1938
Imagery
202
1944
USGS Topo
207
1962
Imagery
211
1995
Imagery
238
2007
Imagery
238
349-330 meters =0.5m/yr
39 years
238-202 meters =0.5m/yr
69 years
Maps and Imagery show that the New Germany Lake Headwaters Marsh Shoreline has
been growing at a rate of 0.5 meters per year (1.6 ft per year) since its establishment.
New Germany Lake Sediments
Surface Sediment
– 8 samples collected in April 2010
– Elemental Analysis showed the same as Core
Samples (no significant enrichments)
– Nutrient Analysis shows slightly enriched
levels of Nitrogen.
New Germany Lake Sediments
Historic data on the composition and growth of
the SAV population in New Germany Lake is
not available.
Experience with deeper mountain lakes indicates
that SAVs are found at water depths greater
than the original water depths of New
Germany Lake.
There is no reason to believe that the decrease in
lake depth caused by sediment deposition has
increased the SAV growth.
New Germany Lake Sediments
• SAV Control Options:
– Aquatic Herbicides
– Biological Control Agents
– Mechanical Harvesting
– Winter Draw Down (Root Freezing)
New Germany Lake Sediments
Summary
•
Sediment Accumulation
Over the course of its ~170 year history, New Germany Lake has accumulated a maximum of
1.8 to 3.8 feet of sediment thickness throughout the majority of the lake, with most sediment
accumulating in the northern portion of the lake. Environmental indicators show that a
majority of this accumulation (76%) occurred before the early 1900s. Sediments that have
accumulated since 1900 range in depth from 3-5 inches.
•
Headwaters Marsh Growth
The delta formed in the headwaters of the lake has shown a consistent history of growth at
1.6 feet/year.
•
Sediment Chemistry
No forms of sediment pollution were identified. Slightly elevated levels of Nitrogen were
detected in the surface sediments.
•
Submerged Aquatic Vegetation
SAV Growth has increased as the lake matured. The population currently inhabiting the lake
includes native species that enhance aquatic habitat.
New Germany Lake Sediments
Management Options
•
Periodically monitor incoming sediment and marsh growth to determine if
rates of deposition or growth have changed.
•
Continue regular control program for Submerged Aquatic Vegetation (SAV) –
This would not affect sedimentation rate but would reduce extent of SAV
beds.
•
Remove accumulated sediment from the lake or selected portions (includes
dewatering facility) – Cost estimates are between 2-5 million dollars. Lake
would be closed for a year or more.
•
Remove accumulated sediment from upper end of lake – Removal of the
existing natural wetland would result in significant ecological impacts and
involve complex wetland permitting and mitigation issues.
•
Explore management options to slow the current rate of growth in the
headwaters marsh
New Germany Lake Sediments
• Ranger Mary Ironside
• Mironside@dnr.state.md.us
•
Dnr.maryland.gov/publiclands/western/newgermany.asp