Greg Risser, William Wall, Steve Brown, Mike Pipak
Professor Charlie Cox
Engineering Design 100
22 April 2013
Runoff Mitigation
Abstract:
The management of storm water is become a more prominent issue as humans alter the
environment around them and more impervious surfaces are added. As we are becoming more
aware of our adverse effects on water quality, we are constantly looking for engineering
solutions to responsibly regulate storm water discharge. Our focus is the mitigation of adverse
runoff effects to create a more sustainable Penn State campus. Our group created a model that
can be used campus wide, but we provide an ideal location in our report. We will identify current
conditions of the Penn State area as it relates to runoff. Next will be what we want to have
changed with the implementation of our project. To see how well our project accomplishes our
goals, we will test the watershed our design affects. After this, we discuss our multiple concepts
and how we chose which one to use. Finally, our solution will be presented, detailing how well
we think it will achieve our goals.
Existing Conditions:
The EPA define sustainability as “Sustainability creates and maintains the conditions
under which humans and nature can exist in productive harmony, that permit fulfilling the social,
economic and other requirements of present and future generations” (EPA 2010). To “maintain
the conditions under which humans and nature can exist in productive harmony,” Penn State
must address the pollution that originates from its University Park campus. Urban runoff
contains multiple pollutants that have negative effects on local and distant ecosystems. The EPA
lists very many types of pollutants that are present, they include: “Sediment from development
and new construction, oil, grease, and toxic chemicals from automobiles, nutrients and pesticides
from turf management and gardening, viruses and bacteria from failing septic systems. Road
salts and heavy metals are examples of pollutants generated in urban areas. Sediments and solids
constitute the largest volume of pollutant loads to receiving waters in urban areas.” (EPA 2012).
As the primary stakeholder of the goal for sustainability, Penn State is constantly mindful
of its effects on the local watersheds because of several reasons. One reason is that Penn State’s
watershed is in close proximity to the State College aquifer therefore polluted runoff could lead
to a contaminated aquifer. Penn State University’s watershed is also a part of the Spring Creek
watershed. Spring Creek is a world renowned trout stream that brings a significant economic
stimulus to the surrounding area. Preserving the quality of this stream is vital to Penn State and
its relationship to its surrounding communities, the other stakeholders.
Currently Pennsylvania State University Park consists of about 653 acres of impervious
surfaces that require 73 miles of drainage pipe. Of the impervious surface area, 67% is located
within the main campus area. Penn State currently has one acre of green roof, 4 designated
watershed basins designated for runoff from campus, and several subsurface water detention
areas to help the moderate storm water runoff. Penn State also uses treated sewage water to
irrigate fields in the Northwest area of campus to safely remove environmentally damaging
phosphates and nitrates (Pennsylvania State University Watersheds Report 2010). State College,
PA sees on average 40 inches of rain per year. This can cause severe flooding issues, adverse
water quality issues, and sinkhole problems dues to the large amount of limestone bedrock in the
area. Large amounts of runoff can also contribute to soil degradation from nutrient losses by
erosion.
We will be using the area by the HUB lawn as a case study for our design. We choose
this area because of a couple reasons. First is that the lawn gets a high amount of foot traffic.
Secondly, the HUB lawn is a well-known place and iconic of Penn State, and we decided that it
should stay a nice as possible. Finally, there is an area at the bottom of the lawn that is plain open
space where our design can be implemented. Our group will address several areas of which we
wish to improve upon in the following preferred conditions paragraph.
Preferred:
Our group wishes to minimize and reuse runoff by slowing water flow and allowing
percolation through the soil profile and into holding tanks to store for later use. By controlling
runoff in this fashion, we would be able to make Penn State more sustainable in water usage,
erosion control, and runoff pollution. By properly controlling the flow of runoff we also want to
have the ability to condense and collect garbage that has been picked up in the runoff. By
condensing trash, we then have the ability to separate it from the runoff. We wish minimize the
total amount of runoff flow by storing the water for reuse at a later time. We can then use this
stored runoff to periodically water high traffic areas of the HUB lawn to encourage more growth
therefore minimizing erosion. By using the stored runoff water at a later time (when the soil is
not saturated) we allow the soil to properly filter the water of runoff contaminants.
To create a solution to the problem, we must identify the owner (Penn State) and other
stakeholders (the surrounding communities) needs. One such owner need is that the design must
be aesthetically pleasing because Penn State must have a high real estate value to attract future
students. Water must be able to percolate through the soil profile quickly to minimize adverse
effects of standing water such as creating mosquito breeding grounds. A suitable rainwater
collection device must be in place and in the event of a heavy rain must have the ability to divert
overflow (of the container) to the present storm water transportation pipes to be safely removed
and drained into Duck Pond. The water that will be contained must have a defined use, and a
source of electricity (such as solar) must be available to accomplish the task. The desired plan
must require minimal maintenance, and minimal upkeep costs. The rain collection device must
also have the ability to consolidate garbage that has been picked up in the current of the runoff.
To address the needs of the surrounding communities our implemented design must not put other
areas at risk for flooding nor cannot hinder the sewage treatment plant in the event of a strong
rainfall.
In order to manage our time when working on this project, we decided to use a Gantt
chart, shown below.
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(Chart 1)
Methodology:
From our research, our group has determined that responsibly managing runoff of the
Penn State University campus is a priority to Penn State. The fact that Penn State has stated that
its effect of watershed is of great importance to the University our group through research has
identified several areas in which Penn State should improve upon. Research by Dietz and
Clausen enabled us to see the possibility of including rain gardens to naturally clean runoff as
part of our solution. Mersie and Seybold (Journal Environmental Quality) found that by slowing
runoff you allow natural removal of runoff pollutants through the soil profile. These are two
qualities that we plan to implement in our design. To determine the effectiveness of our proposed
design, we would test the concentration of pollutants of the Duck Pond watershed. We will
implement a strategy used by Appel and Hudak (Journal of Environmental Health, 2001) that
was used to test runoff in north Texas. Appel and Hudak used the Global Water SS201 storm
water sampler collection device (figure 1) to automatically collect samples from 4 different
areas. Our group will utilize this same device to collect samples from a total of 3 areas. Two
devices will be used in areas of our garden: the portion that the bulk of the run off will be
entering the garden and the area in which water collects and enters the cistern. We also will place
a device at the entrance of Duck Pond to test the effect of our design on the entire Duck Pond
watershed. Once samples are collected, they will be tested for various hydrocarbons, nitrate, and
phosphate compounds. Measurements will be taken before our design is implemented and after;
this would give us an overall effect of our project on reducing the runoff pollutants of the entire
duck pond watershed. To measure our effectiveness on reducing the amount of garbage entering
the Duck Pond watershed, measurements of weight of the garbage collected within our garden
will be taken. This would be an accurate measurement of garbage taken out of the Duck Pond
watershed.
(Figure 1)
Data Analysis
To address the multitude of needs identified in the preferred conditions section a Needs
and Specs chart was created (Chart 2). Each member of our group came up with differing
concepts. They include grated roadways and parking lots, storage bins for water, rain gardens,
greywater use, guards on sidewalks and green roofs. Each of these ideas was evaluated by how
well each met the needs of the stakeholders.
The grating concept consisted of crosshatch concrete placed down as a base for parking
lots. The holes in the parking lot would allow water to drain into the grounds and so lessen the
amount of runoff. Grass would be allowed to grow in these slots which would help with
preventing both point source and nonpoint source erosion. Grating also looks much nicer than
plain parking lot surfaces. This concept works well to meet needs, but not all. For example the
grating doesn’t allow the water to be reused; it just lets the ground absorb it. It also can’t collect
trash, control the movement of water, or store water. These multiple disjunctions between
concept and needs allowed us to rule out the grating idea. This is a drawing of the grating in a
parking lot that has partial grating.
(Figure 2)
Another concept we came up with was to use the runoff as greywater for the toilets.
Greywater is water which isn’t good for drinking or cleaning, but safe enough to be in a toilet.
Greywater is great because it reuses water and it is easy to maintain. The greywater would be
collected from runoff, as well as from the many dishwashers, sinks, showers, and other places
where clean water drains. In order to implement this idea, many gutters would need to be added
to current sidewalks. The addition of these constructions would help with controlling the
movement of water. There are some needs that greywater doesn’t meet. For example, greywater
wouldn’t help with point source and nonpoint source erosion.
Our third strategy, the temporary storage of rainwater, is already being used on campus
by Penn State. One such site is the area under Pegula ice rink currently being constructed. A
series of drainage pipes are organized in such a manner that in the event of a heavy rain, the
pipes can temporarily store runoff to minimize stress on the current drainage system. The water
is not reused for any purposes; it is just stored until it can be safely released into the drainage
system. By storing this water, Penn State creates a cost efficient solution that minimizes the
amount of water that enters the drainage system, but by simply releasing into the current
drainage system they do not clean the runoff. Our group saw this area as an opportunity for
improvement. If we could use the stored runoff as irrigation for an area, we could then use the
soil and plants of that area as natural filters. Areas that could use the irrigation would be nearby
gardens or grass fields that see a high amount of use. This would help ensure healthy grass
growth and therefore minimize the loss of topsoil by erosion. By filtering the water through the
soil profile, Penn State will improve the quality of the water entering the watershed. When water
drains through soil, contaminants such as arsenic, copper, pesticides, and zinc are removed from
it (Filtering and Buffering 2011). This figure from the Soil Quality for Environmental Health
shows what happens as water drains down to the water table.
(Figure 3)
Since our rain collection device will be underground, the area above it can still be
utilized. In the event of a heavy rainfall, our rain collection device must have an overflow present
that drains into the current drainage system, this way we do not flood the surrounding area if the
cistern becomes full. Stainless steel cisterns would be used to ensure that a minimal amount of
maintenance will be needed. The cisterns would have available access through the top to allow
any maintenance that may be required and would eliminate the need to dig the up the cistern.
The green roof concept was another idea that is already in use by several Penn State
buildings (The Dickinson School of Law Building).
(Image taken from Google Images, Figure 5)
We decide to explore this option and see how it could be improved to better serve our
campus. This is a concept that is being applied more frequently worldwide to provide a healthier
environment and is a good fit to promote sustainability on campus. Green roof do many things
that can help reduce negative effects on the environment. First it reduces roof top water run off
by using the water and storing it for use. This reduces pollution and damage from erosion.
Second, roof top gardens naturally insulate the buildings to reduce heating and cooling cost. This
reduces the amount of synthetic insulation that needs to be used in the building as well as
electricity. Also, on average, roof gardens have a positive eye appeal to people which makes
them popular and increases the property value. Not only are roof gardens beneficial to human but
the environment as well. They provide habitat for many insects and are extremely important to
pollinator insects such as bees. Even though this idea seems so great to discuss there is a
drawback, which is the cost. Upon further research t is difficult and costly to convert a building
that is currently constructed from a traditional roof to a roof garden. Several key factors of this
are due to the water and pest resistant berries that need to be in place to keep the building from
deteriorating. Another main factor is the weight of all the vegetation on the roof may be more
than what the older buildings on campus can take. However, new buildings that are being
constructed from ground up are an excellent opportunity to incorporate these gardens on. The
Penn State University has already incorporated this into some of the newer buildings on campus
(the Dickinson School of Law Building), so with this information we decided to focus on a new
idea.
Another avenue our group chose to research was the use of rain gardens. Rain gardens are
becoming more popular in urban areas because of their efficiency, low cost, and the fact they are
extremely aesthetically pleasing. Rain gardens are basically gardens that when flooded have the
natural ability to drain water very rapidly, usually within four hours. The ability to do this lies is
because of the makeup of the soil below the rain garden. The garden consists of three soil layers:
a top soil, followed by sand, and then consolidated rock at the very bottom. The garden then is
filled with plants that have the ability to absorb excess nutrients or pollutants and that are able to
withstand periods of flooding and drought. By using a rain garden as a watershed for nearby
buildings, we minimize the amount of runoff entering the current drainage system and ultimately
entering Duck Pond. We also properly clean the runoff by allowing it to drain through the soil
profile.
The garden would provide an aesthetically pleasing fixture on the Penn State Campus.
By the use of signs, Penn State could also use the garden to inform the public of its purpose and
highlight the benefits of having a rain garden, thus appealing to the increasing green community
and perhaps future students. Because the plants that would be present in the rain garden are able
to survive flood and drought conditions, minimal upkeep is necessary (besides perhaps an annual
weeding). The garden would also provide adequate habitat for multiple organisms including but
not limited to pollinators, songbirds, and waterfowl. Just like our other concepts, an overflow
must be created in the event of a heavy rainfall. The garden cannot put campus and the
surrounding community at risk of flooding if water were to breach the banks of the rain garden.
The figure below is a sketch of the rain garden concept.
(Figure 5)
An existing product that we would need would be a cistern with a three foot diameter and
a height of six feet; this is a product made by Texas Metal Cisterns. Another product to be used
in our design would be different types of plants that can withstand flooding and dehydration.
These are included in chart 2 shown below (Native Plant Center). We would need sensors to
wirelessly tell the operator when the cistern is full. To empty the tank, a pump with pipes will be
inside the tank to get the water out and then to the irrigation sprinklers. Figure 6 shows a
drawing of what our altered cistern would look like. The rooftop of a nearby building can serve
as a site for solar panels that can power the irrigation pump.
(Figure 6)
Plant type
Wildlife Use
Soil
Moisture
Sun
Exposure
Habitat
Grass
Songbirds,
Waterfowl, Small
Mammals
Dry, Moist,
Wet
Full sun,
partial sun
Fresh, brackish tidal and
nontidal marshes, wet
meadows, open woodlots,
prairies, dunes
Deciduous
Tree
Butterflies,
Songbirds, Small
Mammals
Dry, Moist,
Full sun,
Wet, Flooded partial sun,
shade
Drainage basins, mature
flood plains, wooded slopes
Flower
Butterflies
Dry, Moist,
Wet
Full sun,
partial sun
Open woods
Flowering
Shrub
Songbirds, Small
Mammals, Bees
Dry, Moist,
Wet
Full sun,
partial sun
Swamp, spring, old fields,
clearings
(Chart 2)
Our needs versus specifications chart appears below:
(Chart 3)
Conclusion:
Our group concluded that several different proposed solutions are to be implemented in
our final design. In order to minimize that amount of runoff, our group decided to use concepts
of rain storage and rain gardens. Figure 8 shows how the rain garden will be utilized in our
design. The garden will be divided into three different areas. The area closest to the HUB lawn
will consists of flowering plants with a boardwalk going over top this part of the garden to
connect the present walking paths. This part of the garden will be elevated slightly to allow
water to move to the lower part of the garden where the cistern will be placed. The middle of the
garden consists of a long grass that will ensure that flow of the runoff in the garden is slowed and
allowed to enter the soil profile. The final segment of the garden consists of woody shrubs and
trees to continue to slow the flow of the runoff. Also, the higher water needs (compared to the
rest of the plants of the garden) of the trees and woody shrubs are met. The underground cistern
will also be placed in this area because this is where the water will be consolidated. Below,
figures 10 and 11 show sections views of the cistern. Figures 8 and 9 show a model of our
proposed design while figure 7 shows an overhead view of our garden. A gravel spillway will be
placed in the center of our garden will ensure that the area (in the garden) that has the fastest
flow will be able to cause a minimal amount of erosion within the garden. Together our design
minimizes the amount of runoff, and the level of toxicity of that runoff that enters Duck Pond.
(Figure 7)
(Figure 8)
(Figure 9)
(Figure 10)
(Figure 11)
References:
Dietz, Michael E., and John C. Clausen. "Saturation to Improve Pollutant Retention in a Rain
Garden." Environmental Science and Technology 40.4 (2006): 1335-340. Environmental
Science and Technology. ACS Publications. Web. 20 Apr. 2013.
"Filtering and Buffering." Soil Quality For Environmental Health. NRCS East National
Technology Support Center, 19 Sept. 2011. Web. 20 Apr. 2013.
"Managing Urban Runoff." US EPA. Environmental Protection Agency, 22 Aug. 2012. Web. 20
Apr. 2013.
Mersie, Seybold, McNamee, and Huang. "Journal of Environmental Quality." JEQ. Journal of
Environmental Quality, 2013. Web. 20 Apr. 2013.
"What Is Sustainability." EPA. Environmental Protection Agency, 2013. Web. 20 Apr. 2013.
"Native Plant Center." Native Plant Center. N.p., n.d. Web. 22 Apr. 2013.
Pennsylvania University. "Pennsylvania University Watershed Report." Pennsylvania State
University Watersheds Report. Pennsylvania State University, 2010. Web. 22 Apr. 2013.