Flood risk and Soil Study in Sally Ormsby Park

To assess the flooding risk for Sally Ormbsy Park, I used the FEMA (Federal Emergency Management Agency) online interactive tool.  I first searched for Fairfax County, Virginia and then zoomed in on the park and its surrounding residential neighborhood.  Sally Ormsby Park is contained in two FEMA flood plain maps:  51059C0260E and 51059C0280E.  Using a snipping toil, I created one image as seen below taking a portion of each of these flood maps.  The red inked lines I inserted show Barkley Drive as the northern terminus of the park and Prosperity Avenue as the southern terminus of the park.  As can be seen on the map below the entire park is in Zone AE, which is a regulatory floodway.  The residential areas to the west and east of the park are Zone X, which has a .2% Annual Chance of Flood Hazard, which is considered to be an area of minimal flood hazard.

The second image shows the same area, but instead of showing the streets prominently, shows more of an aerial view, but with the vegetation in the floodplain shaded blue.  Again, both Barkley Road and Prosperity Avenue are outlined in red ink to show the north and south boundaries of the park and flooding zones AE and X are shown.

To learn more about the soils of Sally Ormsby Park and this section of the Accotink Creek watershed, I went to the USDA Soil Survey site.  By inputting the state of Virginia and then Fairfax County, I was able to zoom in to Sally Ormsby Park and its environs.  The image below is a soil map of the site.  Once again, I inked in red Barkley Drive to the north and Prosperity Avenue to the south, to delineate the north and south boundaries of the park. 

As can be seen in the map above, the most prominent soil in the park is 29A, followed by 49A in the surrounding area.  Below is the legend for the soil map, which includes these two soils.

In the interactive site, you can click on the soil name and short description and get a readout with more details.  I have provided them below for 29A, the Codorus Silt Loam and 49A, the Hatboro Silt Loam.

29A—Codorus silt loam, 0 to 2 percent slopes, occasionally flooded Map Unit Setting National map unit symbol: 2fjmt Mean annual precipitation: 37 to 49 inches Mean annual air temperature: 45 to 67 degrees F Frost-free period: 185 to 212 days Farmland classification: Not prime farmland
Map Unit Composition Codorus and similar soils: 85 percent Minor components: 5 percent Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Codorus Setting Landform: Flood plains Down-slope shape: Linear Across-slope shape: Linear Parent material: Alluvium derived from igneous, metamorphic and sedimentary rock Typical profile H1 - 0 to 8 inches: silt loam H2 - 8 to 50 inches: loam H3 - 50 to 62 inches: stratified very gravelly sand to loam Properties and qualities Slope: 0 to 2 percent Depth to restrictive feature: More than 80 inches Natural drainage class: Somewhat poorly drained Runoff class: Low Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high (0.57 to 1.98 in/hr) Depth to water table: About 10 to 24 inches Frequency of flooding: Occasional Frequency of ponding: None Available water storage in profile: Moderate (about 8.7 inches)

49A—Hatboro silt loam, 0 to 2 percent slopes, frequently flooded Map Unit Setting National map unit symbol: 2fjpz Mean annual precipitation: 37 to 49 inches Mean annual air temperature: 45 to 67 degrees F Frost-free period: 185 to 212 days Farmland classification: Not prime farmland
Map Unit Composition Hatboro and similar soils: 85 percent Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Hatboro Setting Landform: Flood plains Down-slope shape: Linear Across-slope shape: Linear Parent material: Alluvium derived from igneous and metamorphic rock Typical profile H1 - 0 to 6 inches: silt loam H2 - 6 to 23 inches: loam H3 - 23 to 60 inches: clay loam Properties and qualities Slope: 0 to 2 percent Depth to restrictive feature: More than 80 inches Natural drainage class: Poorly drained Runoff class: Negligible Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high (0.57 to 1.98 in/hr) Depth to water table: About 0 to 18 inches Frequency of flooding: Frequent Frequency of ponding: None Available water storage in profile: Moderate (about 8.6 inches)

Both of these soils are silty loams and their landform is flood plains.  Codorus is somewhat poorly drained and Hatboro is poorly drained.  Neither is prime farmland. 

This information in addition to the FEMA flood risk maps shown above show that a park is a good land use for this section of watershed of Accotink Creek.  In particular, the area on either side of Accotink Creek and Long Branch Creek are regulatory floodways, while the surrounding residential areas have minimal flood hazard.

Resources

FEMA Flood Map Service Center.  Retrieved from https://msc.fema.gov/portal/home .

USDA Natural Resources Conservation Service.  Web Soil Survey.  Retrieved from
https://www.nrcs.usda.gov/wps/portal/nrcs/main/soils/survey/

Plan for Assembling Materials on Accotink Creek in Sally Ormsby Park Watershed Study

My tentative plan is to assemble all my various blog posts on Sally Ormsby Park into usable presentations or documents and then upload them into Canvas's e-Portfolio.  I do have some questions about this process, whether I can assemble them all as one file, or if they would be separate files. 

Also, my Google Slide decks that are embedded in this blog are ones that I would use if I was doing a presentation to an audience about the various topics.  With that in mind, I did not make them text-heavy, because I know that is one of the pitfalls of presentations.  When I do presentations, I do not create speaker notes, because I don't generally need them if I am familiar with a topic, but I need to decide if I should add speaker notes to the slides,

I am planning to discuss these and other topics with my professor, Jim, at our meeting next Tuesday.

Invasive Species in Sally Ormsby Park

Evaluation of Water Monitoring Equipment Suppliers

There are many different methods to evaluate a waterway and an even greater number of companies devoted to supplying the evaluation equipment.  This paper shall serve to mention some of the different methods of evaluation as well as an evaluation of the supply companies.

Audubon International has created a concise fact sheet called Resources for Stream Quality Monitoring (Audubon International).  It lists the following different methods of stream monitoring:  visual surveys, macroinvertebrate surveys, testing for physical characteristics and specific chemical testing.  Visual surveys would consist of looking at the stream for color, surface film, checking odor, litter, etc.  Macroinvertebrate surveys involve sampling the water for insect larvae and worms.  The abundance and variation of the species present gives an indication of the health of the stream.  Testing for physical characteristics includes collecting data on pH, temperature, turbidity, dissolved oxygen and conductivity.  Lastly, specific chemical testing includes measuring the concentration of nitrates, phosphorus, potassium, heavy metals and other compounds.

The NSTA (National Science Teachers Association), on the other hand, has a set of ten different protocols for evaluating streams (Carlsen, W. et al, 2004).  Some of these protocols are similar to the broader categories of Audubon International.  Protocol 5, for instance, is “Collecting aquatic invertebrates to do a survey of biota”.  Protocol 6 is a Simplified Stream Biota Test (SSBT) using data from Protocol 5 to assess the quality of a segment of a stream.  Similarly, Protocol 7 involves a more complicated assessment called an Index of Biotic Integrity (IBI) that also used the data from Protocol 5.  Protocol 8 measures a stream’s discharge, calculating the volume of stream flow, based on water depth and flow velocity.  Protocol 9, Aquatic Chemistry, involves collecting stream samples and analyzing the water using kits.

A dizzying number of businesses supply the equipment professionals and volunteers use to monitor physical, biological and chemical characteristics of streams.  Below, I shall list some of the more prominent companies and organizations that supply this equipment, with a concise description of their offerings.

Ben Meadows—This family-owned company was purchased in August, 2018 by Forestry Suppliers.  The notice on the Ben Meadows website describes the two companies as “friendly competitors” since the 1950’s, with similar values. 

Forestry Suppliers https://www.forestry-suppliers.com/BM/index1.php#  --  This family-owned company sells equipment for forestry, engineering and environmental science.  They sell over a thousand items of water monitoring equipment.  These include data loggers, water samplers, water analysis kits, water testing kits, and stormwater and spill management equipment.  You can search by price point as well as by brand.  A very comprehensive supply company.

In-Situ  https://in-situ.com/ -- In-Situ is an environmental equipment rental company.  It manufactures its own equipment for water quality and water flow monitoring and appears to be directed more towards the professional than a volunteer water evaluator.  In-Situ provides 24/7 technical support.  They also sell their products, but do not list the price on the website.  You need to contact them for a quote.

SOS (Save Our Streams), Izaak Walton League  https://www.iwla.org/conservation/water/save-our-streams -- Save our Streams is a citizen science program sponsored by the Izaak Walton League.  They recommend various chemical and physical monitoring equipment designed for volunteers and have links to companies that sell these items.  They also supply data forms and encourage you to share your data with the League, so that they can compile and use it.

Chemetics—This company offered kits for measuring various chemical properties, but was purchased by Worley in April 2019.

BioQuip Products https://www.bioquip.com/ --  BioQuip is a small company that sells equipment, supplies and books related to entomology and other biological concentrations.  It is a helpful source for stream monitoring using the NSTA’s Protocol 5.  Products include specialized collecting nets, magnifiers, books, educational materials and water sampling chambers.

YSI https://www.ysi.com/ -- YSI is a large company that sells every possible product you can imagine for assessing fresh and salt water bodies, stormwater and wastewater.  It is geared more towards the professional than the volunteer.  It offers extensive customer support and sponsors educational blogs as well as trouble-shooting articles (e.g. 5 Tips to Prevent Costly Mistakes with your Water Quality Sonde). 

LaMotte https://www.lamotte.com/en/ -- LaMotte’s website says they have been “solving analytical challenges since 1919”.  Many of their products have to do with pools and spas, drinking water and aquaculture.  However, they do have a full line of products for environmental education.  These include water monitoring kits, test strips, and bacteria studies kits.

Carolina Biological Supply Company https://www.carolina.com/ -- This company carries educational products for many natural and physical science curricula.  It sells the Earth Force Low-Cost Water Quality Monitoring Kit, developed in cooperation with Global Rivers Environmental Education Network (GREEN).  The kit tests temperature, turbidity, pH, dissolved oxygen, nitrates, phosphate and coliforms.

Acorn Naturalists https://www.acornnaturalists.com/ -- This environmental company sells educational products “for Trail and Classroom”.  Their website states that after 30 years of evaluating water quality test kits, they find LaMotte kits to be the best.  They offer a full array of LaMotte water quality test kits, including their GREEN (mentioned above in Carolina Biological Supply Company review) water quality monitoring kits.

Fondriest Environmental, Inc. https://www.fondriest.com/ -- Fondriest rents and sells many brands of equipment, including their own, In-Situ, YSI and Hach.  Their merchandise is directed towards the professional, rather than the volunteer.  They sell over 1700 water quality products alone.

Flinn Scientific https://www.flinnsci.com/ -- This company sells products for earth and environmental science.  It sells water samplers, water quality field trip kits, water sampling supplies and a DO kit.

Hach https://www.hach.com/ -- Founded in 1933, Hach specializes in water analysis.  Its products are geared towards the professional and most products are for continuous monitoring. 

Resources

Audubon International. Resources for Stream Quality Monitoring.   https://auduboninternational.org/wp-content/uploads/2019/03/WQ-Stream-Quality-Monitoring-Resources.pdf

Carlsen, W., Trautmann, N., Krasy, M. & Cunningham, Ct. (2004) Watershed Dynamics, Student Edition and Teachers’ Manual.  Arlington:  NSTA Press.

More About the Trees of Sally Ormsby Park

Other watershed studies

For those who are interested in reading about other watershed studies, I am listing below my classmates in Virginia Tech’s Watershed Stewardship class.  Please read and enjoy:

Amy - Lake Michigan (IL,MI,WI) (Links to an external site.)
Bill B. - St. Francis River (AR) (Links to an external site.)
Brenda - Lynnhaven River (VA) (Links to an external site.)
Christina - San Lorenzo River (CA) (Links to an external site.)
Daniel - Trout Run (VA) (Links to an external site.)
Emily - Occoquan River (VA) (Links to an external site.)
Jeremy - Yakima River (WA) (Links to an external site.)
Jessica - Yellowstone River (MT,WY) (Links to an external site.)
Jim - Potomac South Branch (WV) (Links to an external site.)
Jim - Potomac South Branch (Fcbk) (Links to an external site.)
Joel - Everglades (FL) (Links to an external site.)
Kayla - Hood Canal (WA) (Links to an external site.)
Lacy - Stemple Creek (CA) (Links to an external site.)
Marie - Schuylkill River (PA) (Links to an external site.)
Nichole - Pugent Sound (WA) (Links to an external site.)
Nikolai - Kailua (HI) (Links to an external site.)
Roxanne - Accotink Creek (VA) (Links to an external site.)
Ryan - Octoraro Creek (PA) (Links to an external site.)
Samara - Gorst Creek (CA) (Links to an external site.)
Theresa - N. Anna River (VA) (Links to an external site.)
Thomas - Eno River (NC) (Links to an external site.)
Will C. - Upper Tennessee (VA)

Friends of Accotink Creek

Urban Archery Program in Sally Ormsby Park

One cannot walk through Sally Ormsby Park without seeing the above image, declaring the archery hunting season within the park from September 7. 2019 to February 22, 2020.  To some, these signs may come as a surprise, since the park lies in the middle of suburbia.  However, an investigation of the website on the sign reveals further information about the program and its benefits. 

Virginia’s Urban Archery Program began in 2002 as a means to control the increasing population of white-tail deer.  Because man has eliminated the natural predators of white-tail deer (namely wolves, black bears and mountain lions) in urban Virginia, the white-tail deer population in many areas of the Commonwealth is estimated to be higher than it was when Europeans first settled in Jamestown.  The result is that watersheds like Accotink Creek’s watershed in Sally Ormbsy Park are being over-browsed.  Native shrubs and native herbaceous plants covering the forest floor are decimated by the dense deer population, causing erosion in many places where there is a lack of the multiple layers that a healthy forest habitat would have.  This results in increased erosion and sedimentation in the creek.  On the other hand, in some areas of the watershed, invasives like multi-flora rose and oriental bittersweet (both shunned by deer) have replaced the native plants, thereby decreasing the habitat value of the watershed.  Also, an over-browsed forest is unable to regenerate itself. 

The program has a humanitarian element as well.  In urban and suburban areas that have an overpopulation of deer, many of the deer will starve to death in the winter when they have removed all the browse within their reach.

The Urban Archery Program has an excellent safety record and is strictly managed.  Since archery accidents started being managed in 1959, there have been no injuries to bystanders in Virginia.  The archers must obtain a permit that gives them a particular area where they may hunt and they may only hunt from 30 minutes before sunrise until 30 minutes after sunrise, from Monday through Saturday.  They can only hunt from tree stands, which they must build themselves and they must use safety harnesses within the tree stands.  If a shot misses a deer, because they are shooting from above at close range, the arrow will go downwards into the dirt.

The archer must field dress the deer out of sight of the public, leaving the entrails in the woods out of sight and preferably covered with earth or leaves.  They must also retrieve any stray arrows from misses and report any injured deer that was not felled by the arrow. 

In 2013 alone, 848 deer were removed from Fairfax County parks by archers, providing a significant decrease to the deer population.  If you include archery hunting on private lands, the average number of deer killed each year is about 1500.

The Urban Archery Program in Sally Ormsby Park has been a win-win situation.  It benefits the health of the watershed by decreasing over-browsing.  It benefits the other native wildlife besides deer who need the cover and food provided by the forest shrub and forest floor layers.  It benefits the archers, who are permitted to eat the venison from deer they have killed.  And, it prevents many of the deer from having a slow, miserable death from winter starvation.

Flooding of Accotink Creek and Flood Data from nearby Gauges

The National Oceanic and Atmospheric Association's National Weather Service maintains a website with current data measuring water levels at hundreds of river gauges around the country.  The two closest gauges to Accotink Creek are on the Potomac River near Washington D.C. at Little Falls, MD and on the Potomac River in Georgetown (in Washington, DC).  By going to the following web page https://water.weather.gov/ahps/ and selecting Virginia, you can then zoom in on Fairfax County and finally find Sally Ormsby Park with Accotink Creek running through it.

By Zooming out a bit, you find the two aforementioned gauges.  Below is a map that shows the Little Falls gauge with its current water levels.

As you can see, the river is well below flood level now, largely because of the drought of the last 6 weeks, when the Greater Washington DC area has received very little rain.  The next map shows the probability of floods at this gauge in the next month.

The above graph shows that the chances of reaching even lower flood levels during the next month are less than 10%.

I also examined the data on the Georgetown gauge location of the Potomac River.  Below is a graph of river levels at that gauge.

What is noteworthy here is that the water levels of the Potomac in Georgetown rise and fall twice a day.  This is undoubtedly because of tidal action on the river.

An additional piece of information on the website for Georgetown is that it shows inundation areas.  Below is the photo from today.

You can see that there are no areas near the river that are currently inundated, but during a flood, they would be captured on this satellite image.

A search for recent flooding on Accotink Creek resulted in a Patch.com article about flooding on July 24, 2018.  Warnings were sent out to subscribers of the Patch site that the creek had flooded Woodburn Road in Annandale (not far from Sally Ormsby Park) .  Below is a photo of an abandoned car on Woodburn Road during that flood.

Steve Chenevey Fox5

The full story of this flood on Accotink Creek can be found at https://patch.com/virginia/annandale/moving-flood-waters-trap-car-annandale-photos .

Native trees in Sally Ormsby Park

This morning, I had a very pleasant walk through the Sally Ormsby Park watershed of Accotink Creek and inventoried and photographed the trees.  Below are the species that I found.  I am not 100% certain about the oaks (we have so many species of oaks in northern Virginia!), but did my best to identify them.  The other species,, I am very familiar with and many can identify by the bark alone.

Eastern Sycamore, Plantanus occidentalis
American Beech, Fagus grandifolia
Red Maple, Acer rubrum
River Birch, Betula nigra
Box Elder, Acer negundo
Tulip Tree, Liriodendron tulipifera
Sweet Gum, Liquidambar styraciflua
American Hornbeam, Carpinus caroliniana
Black Cherry, Prunus serotina
White Oak, Quercus alba
Northern Red Oak, Quercus rubra
Southern Red Oak, Quercus falcata
Black Oak, Quercus velutina

Topo map of watershed

Below is a topographic map of Sally Ormsby Park and Accotink Creek.  The area within the red ink is the study area.

The sticky note at the top of the map denotes the elevation of 270 feet where Accotink Creek enters Sally Ormsby Park. The sticky note at the bottom of the map denotes the elevation of 260 feet where the creek leaves the park.  So, there is only a 10 feet elevation loss in the park.  About a 100 yards northwest on the Cross County Trail from eastern boundary of the park, there is a footbridge across the creek.

Terrain View of Sally Ormsby Park Watershed

Below is a My Maps Google Map of the study area with a terrain view.

Accotink Creek on September 1, 2019

I first came to Sally Ormsby Park on September 1, 2019 and decided to choose the park as the watershed to study.  I noticed that the creek was fairly low, as we had had little rain the past several weeks, and that the shores of the creek were badly eroded in places.

Welcome!

Welcome to the Sally Ormsby Park Watershed Study blog.  The purpose of this blog is to serve as an online journal to study the section of Accotink Creek and its watershed within Sally Ormsby Park in Fairfax County, Virginia.