Introduction
Study Area
Results
Interpretation and Discussion
Works Cited
Web Sources
Introduction (Back
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Water quality throughout the Rappahannock River is dependent
on a variety of factors. Increased development throughout this area
has led to significant declines in the quality of the water. Our purpose
was to look at these changes occurring specifically in Massaponax Creek,
due to its proximity to current changes in land use. The main areas
which will be addressed concerning the Massaponax Creek and its ever-increasing
degradation include: nutrient pollution, overall water quality, land
use, common runoff processes, the importance of best management practices,
and their effects on the status of this creek.
Study Area (Back
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The Rappahannock River Basin is located in the northeastern
portion of Virginia, just south of Washington, DC. This basin covers
about 184 miles in length and 20 to 50 miles in width, representing
one of the major tributaries of the Chesapeake Bay (VA DEQ, 1997). Our
site, Massaponax Creek, is located in Spotsylvania County, about two
miles south of Fredericksburg, Virginia. This creek flows directly between
Interstate 95 and US Route 1. For the most part, this area is comprised
of rolling hills and a few isolated ridges. The vegetation throughout
Massaponax Creek consists of a few trees near the creek's edge. We did
notice a significant decline in the abundance of vegetation, observing
clear cutting and other disturbances. The climate of the area is temperate
oceanic, similar to sub-tropical, which is somewhat humid and wet. The
climatological normals, calculated with data from 1961-1990, show that
the area around Fredericksburg receives roughly 40 inches of precipitation
per year (Climatological Normals, 1990). Massaponax Creek, located in
the lower Rappahannock sub-basin, is 47.5 miles long, representing about
23,178 acres of area (Lease, 1992). The creek itself is fairly narrow
with some clay on the sides and a gravel, sand bottom. Land use surrounding
Massaponax Creek has changed significantly over the past thirty years.
In 1963, the land use was mostly woodland, with some agricultural cropland.
By 1989, the land had been converted to mostly residential, commercial,
and industrial use. In 1963, only 5% of the area was developed, in comparison
to over 29% developed in 1989 (Sullivan, 1992).
Massaponax Creek is located in unit E20, representing
one of the 26 hydrologic units in the Rappahannock Basin. Many reasons
exist concerning our choice of this study site. The increasing levels
of development have resulted in this area being one of only three units
assigned a "high" ranking for urban activity. This watershed
also represents one of seven which has been assigned a "high"
ranking for overall nonpoint source pollution. The State Water Control
Board recognizes high nutrient levels, assigning a water quality standard
of "nutrient enriched waters" and an overall assessment of
"threatened" for aquatic life (VA DEQ, 1997).
Results(Back
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We visited the following sites on March 24, 1998 and April
8, 1998, collecting water samples, examining the surrounding areas and
land use, and taking photographs of pertinent information.
Site #1: Deerfield (Rt. 673)
Located on the headwaters of the creek, this site is about
15 feet wide, with only a one foot bank. The soils of this stretch of
the creek are clay sandy banks. This area is forested, with large amounts
of leaf litter. This site actually flows under the Route 673 bypass.
Housing developments were observed in close proximity to the sampling
area.
Site #2: Massaponax Outlet Center
This site is located approximately 150-200 yards from
Interstate 95, on the southern end of the creek. This segment was about
30 to 50 feet wide, with 10-foot banks. Sandy soils were also present,
along with a number of sandbars. The vegetation of this area was predominantly
perennial grasses. The flow of this area was significantly faster than
other areas.
Site #3: Lee's Hill Golf Course
This site is located on the northern end of the creek,
north of Route 17. The width of this segment of the creek was approximately
20 feet wide. The banks had been enhanced with conventional stream armoring,
such as rip rap, reaching nearly 15 feet in height. Sandy soils were
once again observed. The tree cover was more abundant, creating a 15
to 20 foot buffer zone. There was also a presence of low leaf litter.
We observed a stark contrast between the normal flora of the area and
what was present on the golf course. There was a significantly "greener"
appearance, probably due to the use of heavy fertilizers.
Site #4: Route 608
This site is located approximately 25 yards from the train
tracks in a culvert. The width of the reach was approximately 40 feet
with 20-foot banks, consisting mainly of large stabilized conglomerates.
Discharge was swift due to heavy rains in the days prior to sampling.
The soils were made up of cobble-sized sands and clays. The vegetation
was fairly light with weeds and riprap lining the creek.
Site #5: Route 609
Located on the eastern end of Massaponax Creek, this site
was about 50 feet from the road. The width of this stretch of the creek
was about 20 feet, with a bank full height of 2 feet. Sandy soils were
covered with a thick leaf litter, due to the surrounding forested area.
The most obvious observation was the buildup of foam resulting from
the output from two drainage pipes. We also observed large quantities
of debris, such as: tires, mattresses, trash bags, wires, and other
items.
Site #6: Ruffin's Pond
This site is on the northeastern end of Massaponax Creek.
A large industrial park and a small airport are located within a few
miles of the pond. The width was greater than 100 feet due to its proximity
to the confluence with the Rappahannock River. We observed sandy soils
and dense vegetation in this undeveloped area.
The water samples collected were tested using Hach chemical
kits. We tested specifically for orthophosphate and nitrite. We also
compiled information from the ambient water quality monitoring station
(3-MAP002.61), located on Route 609. This station undergoes quarterly
monitoring, administered by the Department of Environmental Quality.
The parameters tested by the DEQ are total nitrogen, orthophosphate,
nitrate, nitrite, and dissolved oxygen levels.
Refer to Table 1 for this information.
The average levels for orthophosphate and total nitrogen are 0.03 and
0.6 mg/L, respectively (Chesapeake Bay Program). The nitrite values
found through these testing methods were inconsistent and will not be
addressed within the discussion.
Table
1: Water Quality Data for Massaponax Creek Sites
Interpretation and Discussion
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The quality of water is important because it affects the
quantity of water, wildlife diversity, human health, and aesthetics.
Our study showed how the rise of various factors causes degradation
near Massaponax Creek. Developmental pressures and severe increases
in land use are the major sources of water quality degradation in Massaponax
Creek. An increase in the amounts of runoff and population has added
to the problem. Nonpoint source pollution and competition for water
resources are other variables that decrease the quality of the water.
Nutrient pollution is one of the major concerns facing
Massaponax Creek. Nutrients, such as nitrogen and phosphorous, occur
naturally in the water, soil, and air, and are extremely critical to
the growth of aquatic life. Nitrogen aids in the production of plant
and animal tissue, while phosphorus plays a role in cellular growth
and reproduction. The problem arises when these nutrients appear in
excess, creating a significant increase in rate of plant growth often
yielding an alga bloom. The process of eutrophication leads to a decreased
amount of available sunlight. The plants are left without their necessary
light requirements. As this alga dies and decays, the oxygen demand
of the water is increased, typically yielding a decreased dissolved
oxygen level, ultimately leading to bacterial degradation, fish kills,
and other threats to aquatic life (Chesapeake Bay Program).
Nutrients enter waterways through a variety of different
sources and mechanisms. Agricultural runoff represents the greatest
single contributor of nitrogen and phosphorous. Orthophosphates are
applied to agricultural land as fertilizer, which is absorbed into the
soil, becoming strongly bound to these particles. Other sources of phosphorous
include domestic sewage and animal wastes. Low concentrations of phosphorous
may leach into the groundwater, eventually entering the streams. Larger
amounts are carried be eroded soil particles and runoff. Dissolved and
solid forms of phosphates may be carried by both Horton overland flow
and Saturated overland flow (Dunne, 1978).
The sources of nitrogen are typically similar to phosphate's
origins. Nitrogen, however, exists in a variety of forms. Ammonium,
in the process of being degraded, is typically found in organic debris.
This ammonium becomes absorbed to the soil and is lost by erosion. Nitrites
are commonly found in anaerobic environments such as waterlogged soils.
Nitrates represent the fully oxidized form of stable nitrogen compounds,
which is common in most surface runoff (Baird, 1995). Nitrates are highly
mobile, moving easily through the crop root zone, especially in sandy
soils, which make up the geology of this creek. A small portion may
be transported with surface runoff (Dunne, 1978). The existence of various
land use practices has a significant effect on the type and amount of
nutrient pollution reaching Massaponax Creek.
The drainage basin of Massaponnax Creek is enveloped within
one of the fastest growing counties in the state of Virginia, Spotsylvania
County. Over the past 25 years, the land use of the surrounding terrain
has changed the hydrology of the creek and is currently affecting the
creek's productivity. What used to be an area of rural county farms
and forest with a few scattered neighbors is now taking on the outlook
of becoming an urban center; significant growth and environmental stress
is occurring in the Massaponax watershed.
The predominant land use in Spotsylvania County is comprised
of wooded, underdeveloped, or agricultural land amounting to 75% of
the land (Spotsylvania County Planning Commission, 1994). The remaining
land is dictated by development: mostly residential followed by industrial
and commercial areas. Included in the latter is Massaponax Creek.
Figure
1: Land Use Near the Massaponax Watershed.
Various types of land use in the
Massaponax watershed affect the water quality in numerous
ways. Figure 1 illustrates this land use. Also taken
into consideration during observations were the active hydrological
processes taking place. Some processes observed include Horton Overland
Flow (HOF), Shallow Subsurface Storm Flow (SSSF), and Saturation Overland
Flow (SOF). HOF is defined as precipitation being greater than the infiltration
capacity of the soil. SSSF occurs when the water that has infiltrated
the groundwater hits a permeability boundary and flows laterally into
a channel, sometimes seeping out of the hillside. SOF demonstrates saturation
excess as the water table rises and intersects the hillslope at its
base indicating channel saturation (Dunne, 1978).
Beginning at the western end of the watershed:
Site #1, Deerfield , which is representative
of residential landuse. SOF was observed. We hypothesized findings of
low to moderate nutrient concentrations. We recorded a phosphorus value
that supported this. The sources of the nutrients in residential area
is typically due to fertilizers being transported by erosion and runoff
as well as storm water runoff, often carrying domestic sewage
Site #2, Massaponnax Outlet Center ,
represents commercial landuse. We hypothesized findings of moderate
nutrient concentrations assisted by high storm runoff and HOF due to
increased impervious surfaces. We recorded a P value slightly higher
than expected and attribute this to a recent storm event.
Site #3, Lee's Hill Golf Course , represents
residential/recreational landuse. We hypothesized findings of high nutrient
levels due to abundant use of fertilizers transported by SSSF and storm
runoff. We recorded P values of 0. This discrepancy is most likely attributed
to nutrient washout due to a recent storm event. Another possibility
is that the evidence of fertilizer may show up further downstream and
therefore is not affecting this immediate area.
Site #4, Rt. 608 , represents lightly
industrialized landuse. SOF was observed. We hypothesized findings of
moderate to high nutrient levels due to the stormwater runoff from this
somewhat urban area. Our results indicate a very high level of orthophosphate.
This high level may have resulted from its location immediately downstream
from Lee's Hill golf course
Site #5, Route 609 , represents light
industrial and somewhat commercial land use. SOF was observed. Our expectations
were a finding of moderate to high nutrient levels due to this land
use. For this site we have actual data from the Department of Environmental
Quality. Our results, taken on both sampling days, indicate a variance
between somewhat low to high levels. The data from DEQ indicates a variance
of low to moderate orthophosphate concentrations. Both findings show
a somewhat lower concentration than expected, probably due to the extensive
riparian buffer regions on either side of the creek.
Site #6, Ruffins Pond , represents an
area which is fairly undeveloped, wetland. We hypothesized findings
of low nutrient levels. Our findings indicate orthophosphate concentrations
higher than expected, probably due to this site's proximity to Massaponax
wastewater treatment plant and its location at the mouth of the creek,
therefore accumulating higher amounts of contamination.
In all, Massaponax Creek represents a diverse system of
varying land use processes and consequential effects upon the health
of the waterway. According to Estalena Thomas, natural resource planner
for the Chesapeake Bay Foundation, "The Massaponax Creek watershed
is the Chesapeake Bay in miniature" (Lease, 1992). The problems
found in the Bay are present here and the problem must be addressed
throughout all streams and tributaries, for they ultimately have an
effect on the Bay itself. Two management practices examined include
the use of Riparian Buffers and Conservation Tillage. Riparian buffers
attempt to stop nutrients from entering waterways through absorption,
specifically through denitrification and plant uptake. The plants that
absorb nutrients also control erosion of sediment with their roots and
leaf litter. Conservation Tillage prevents runoff by increasing crop
residue. Crop residue in turn protects soil from erosion by preventing
direct rainfall impact on soil particles. By preventing direct impact,
the likelihood of nutrient and sediment entrainment into solution is
decreased.
Works Cited (Back
to Top)
Anderson, K. 1997. A Land Use Assessment of the Deep Run
and Alcotti Run Watersheds.
Baird, Colin. 1995. Environmental Chemistry. W.H. Freeman
and Company, New York, 484 p.
Burke, Robert. 1997. No Quick Fix for Problem Plant. The
Free Lance Star, Section C, p.1-2.
Burke, Robert. 1997. Spotsylvania Sewage Leaked Into River.
The Free Lance Star, p.A1.
Carrillo, Maria. Aug.12, 1992. Vigilance is Key in Years
Ahead. The Free Lance Star, p.A1-A10.
Commonwealth of Virginia. 1996. Shenandoah and Potomac
River Basins Tributary Nutrient Reduction Strategy. p.30-35.
Dunne, T.L. and Leopold, L.B. 1978. Water in Environmental
Planning. W.H. Freeman and Company, New York, 818 p.
Heatwole, Conrad. 1991. Agricultural BMPs Applicable to
Virginia, Bulletin 169, p.1-20, 45-50.
Jones, R. Christian. 1985. Effects of Land Use Practices
on Water Resources in Virginia, Bulletin 144, p.14-15.
Journal of Soil and Water Conservation. May-June 1983.
Vol.38, Number 3, p.188-192.
Kuo, A.Y., Moustafa, M.Z., and Park, K. 1991. Spatial
and Temporal Variabilities of Hypoxia in the Rappahannock River, Virginia.
Estuaries, v.14, p.113-121.
Lease, Daryl. Aug.10, 1992. Invaded and Ignored. The Free
Lance Star, p.A1- A8.
NRCS Virginia. 1996. Riparian Forest Buffer. p.1-10.
Spotsylvania County Planning Commission. November 1994.
Spotsylvania County Comprehensive Plan, p.63-66.
Sullivan, Paul. Aug.11, 1992. Caught in the Area's Land
Rush. The Free Lance Star, p.A1-A8.
U.S. Army Corps of Engineers. 1998. Riparian Buffers and
Streambank Restoration as a Cost Effective Water Quality Best Management
Practice. p.1-6.
Virginia Department of Conservation and Recreation. 1996.
Nonpoint Source Pollution and You.
Virginia Department of Environmental Quality, Virginia
Department of Conservation and Recreation, and Chesapeake Bay Local
Assistance Department. 1995. Virginia's Potomac Basin Tributary Nutrient
Reduction Strategy. p.58.
VA DEQ and VA DCR. April 1996. Virginia Water Quality
Assessment for 1996 and Non-point Source Pollution
Watershed Assessment Report. 305(b) Report to EPA and
Congress, p.1-6.
Virginia Department of Environmental Quality. 1997. Water
Quality Monitoring in the Rappahannock River Basin, p.35.
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Web Sources
Chesapeake Bay Program: Environmental Indicators, www.chesapeakebay.net/bayprogram/measure/indicatr/npcb.htm
The Chesapeake Bay Program Nutrient Reduction: Defining
Nutrient Pollution, www.chesapeakebay.net/bayprogram/restore/nutrient/nutrfaq1.htm
Climatological Normals,
www.people.Virginia.edu/~cl.mate/normals/443192_30yr_norm.html
Fish Health in the Chesapeake Bay: Pfiesteria piscicida
,
www.mdsg.umd.edu/fish-health/pfiesteria/index.htm
Land Use, Water Quality, and Quantity.
www.iwr.msu.edu/edmodule/water/wtrfrm1.htm
Procedures for Indexing Monthly Non point source pollution,
Gene Yagow, www.epa.gov/owowwtr1/watershed/Proceed/yagow.htm
The Rappahannock and the Chesapeake Bay,
www.gmu.edu/bios/bay/acb/facts/rappahan.htm
Travelocity, Charles Babington and Ellen Nakashima, washingtonpost.com
Virginia Fact Sheet,
www.va.usgs.gov/GLOBAL/factsheet.html#HDR3
Va. Moves Forward on Tributary Strategies, Monitoring.
http:\\web.gmu.edu/bios/bay/journal/94-09/virginia.htm
Water Quality Problems,
www.epa.gov/gumpo/emap/module7.html
Water Quality Q-Value Graphs,
http:\\gilligan.esu7.K12.ne.us/1web/water/qvaluegraph.htm
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