Baker Butler Elementary School: Lower Site Retrofit by Summer Xiang

Baker Butler Elementary School:

Lower Site Retrofit 2015 Camille Adkins, Isabel Preciado, Arthur Baiochi, Summer Xiang

Introduction B a ke r B u t l e r E l e m e n t a r y S c h o o l is located in the Northwest section of Albemarle County. As the Baker Butler Upper Site Report mentions, the site is located along the South Fork Rivanna River Watershed. Three springs run along the site, and are deposited into Powell Creek, which later flows into the Rivanna River. Currently, Powell Creek is identified as having a “fair ” water quality standard, based on the Health of Rivanna Watershed Streams Report 1 . Although StreamWatch has not detected any trend of improvement or further degradation for the Rivanna system as a whole, streams rated “fair” or worse fail to meet the Virginia water quality standard for aquatic life2. Therefore, it is our goal as a team to improve the conditions of the stream that flow into Powell Creek in order to improve the creek's water quality. The Baker Butler Lower Site is 232,211 sq. ft. in size and around 17% of its area is composed of impervious surfaces. The site has five main features: a stream that

runs along it, a trail that goes from one end to another, a bioretention basin where the stormwater runoff from the upper site is deposited, an elevated baseball field, and a parking lot with an impervious surface and heavy cracking from runoff collection (see Appendix: Figures 1 and 2). By inputting the site data into the N ati o nal Sto rmw ater C al c ul ato r 3 , we calculated the current average annual runoff as 6.97 inches, which is 1,008,944.3 gallons multiplied by the area (see Appendix: Chart 1). In order to retrofit the site for better stormwater management, there are five main challenges that must be addressed: 1. The failure of a retaining wall bank which is tampering with the stream 2. Heavy sediment runoff along the trail path; specifically due to the dramatic drop at the beginning of the trail and the lack of path definition along this slope. 3. An impervious and infrequently used parking lot at the edge of the site with

heavy cracking from water runoff. 4. Soil erosion on the hill of the baseball field and along the stream bank. 5. A lack of art installations, which does not address the original art theme of the trail. As a team, our main goals are to retrofit the site into an educational green trail, while reducing the imper vious surfaces of the site from 17% to 8.6% and the amount of stormwater runoff by 45.3%: from 6.97 inches to 3.87 inches, a p p rox i m a t e l y 5 5 1 , 5 1 7 . 6 g a l l o n s . I n order to accomplish such goals, we have established five solutions in hierarchical order to retrofit the site successfully: 1. Repair existing retaining wall by designing a new green retaining wall.

2. Add fascines, xeriscaping, and soil amendments to control erosion in key places along the site. 3. Change materiality of the beginning of the trail to pervious pavement and curve trail along slope to decrease and direct soil runoff. 4. Design a small bioswale at the end of the impervious parking lot to collect runoff. 5. Add sculptured playground and stormwater ar t to reintroduce the educational theme and manage stormwater in a fun and interactive way for the children. To address all the challenges in detail, the site has been divided into four different sections. Appendix Figure 3 illustrates the four different zones.

"Biological Health of Streams and Rivers of the Rivanna River Watershed." Stream Watch, 2014. Accessed April 27, 2015. http://streamwatch.org/reports. 2

"Biological Health of Streams and Rivers of the Rivanna River Watershed." Stream Watch, 2014. Accessed April 27, 2015. http://streamwatch.org/reports. 3

EPA. 2014. National Stormwater Calculator Userâ&#x20AC;&#x2122;s Guide. Manual, Washington. D. C.: Office of Research and Development National Risk Management Research Laboratory.

ZONE 1: Trail Gateway Problem 1. The entrance of the trail is unnoticeable. 2. The trail path is bare with significant soil erosion problems. 3. There is considerable sediment runoff along the trail due to a drastic slope.

Figure 1. The current entrance of the trail.

Figure 2: the current trail in zone 1 along the slope

Technologies

the entrance and along the trail.

The following strategies are listed in order of priority:

â&#x2014;? U s e i n o rg a n i c s o i l a m e n d m e n t method to change the soil structure and loosen the compacted surface.

1. A sign to emphasize the entrance of the trail. Add a new sign to the left of the trail entrance to make the gateway more conspicuous and attractive. 2. R e i n f o r c e t h e s o i l w i t h s o i l amendments4 and add vegetation both at

Figure 3: Trail entrance retrofit

â&#x2014;? Re-vegetate bare ground surface by planting trees and bushes. 3. Permeable pavement: Interlocking concrete pavers and lattice concrete5 are recommended for the following reasons:

● Excellent for use within a watershed, withstanding freezing and snowplows6. ● It requires low-cost maintenance, at an average price of $ 0.17/ sq. ft. to pressure wash every three years7. ● It is easy to remove and replace8. We strongly recommend permeable pavement in Zone 1, especially on the slope, to solve the serious sediment runoff problem. If possible, we also recommend to apply this strategy along the whole path to create a more coherent, convenient, and dynamic trail for children. 1

Chollak, T. and P. Rosenfeld. “Guidelines For Landscaping with Compost-Amended Soils”. University of Washington College of Forest Resources, 1998. 2

ICPI—Interlocking Concrete Pavement Institute. 2014. “Sustainability and Interlocking Concrete Pavements.” “Frequently Asked Questions—permeable pavement.” Accessed March 2, 2015. http://www.icpi.org/faq/48

Figure 4: Trail gradient retrofit

Chiras, Dan. 2009. "Permeable Pavers: Patios, Walkways, and Driveways Made of Porous Pavement." Mother Earth News. Last modified May 1, 2009. Accessed February 22, 2015. http://www.motherearthnews.com/green-homes/permeable-paversporous-pavement-zmaz09amzraw.aspx#axzz3Ool78K4h 6

ICPI—Interlocking Concrete Pavement Institute. 2014. “Sustainability and Interlocking Concrete Pavements.”“Frequently Asked Questions—permeable pavement.” Accessed March 2, 2015. http://www.icpi.org/faq/4

Zone 2: Wonder Trail Problem There are three main problems in the second section of the site: 1. Falling retention wall: this is one of the biggest problems of the whole site. There is one retention wall responsible for holding the hill directly above the stream and thus supporting the bus parking lot above. The problem is: the wall is falling. If this wall falls there might be severe structural problems with the stability of the parking lot.

Figure 5: The existing retaining wall.

2. Stream bank erosion and bare, unprotected roots: the riverside is completely eroded, leaving roots are exposed. Also, some trees have already fallen into the river, which shows the level of erosion that this area is going under. This is a main problem that should be addressed. 3. Sewer line runs along the trail: This is not really a problem, but it is a design limit factor that must be taken into consideration.

Figure 6: Failing retaining wall with fallen riprap obstructing stream flow.

Technologies 1. Replace the green wall with a more resistant living retention wall.

is obstructing stream flow. Thus r reapplying them in a more stable an help to prevent any standing water w

2. Re-grade the bank.

● The south bank of the stream available for re-grading9.

Figure 7: Regraded stream bank Source: stream restoration lecture by Karen Firehock

3. Stabilize the bank with bioengineering by the following methods: 1) Riprap combined with bioengineering. The reasons to apply it are as follows. ● There are some areas with severe erosion, which would require riprap for stability. ● The existing riprap has fallen into the stream and

Figure 8: Riprap installation Source: stream restoration lecture by Ka

2) Live cuttings: The simplest installed by cutting a trim off a tree point, and inserting ⅔ of it into the b

9,10,1

Firehock, Karen. Storm Restoration Lecture. 2

removing these rocks and nd effective way would also within the stream.

m is steep with little space

Figure 9: Live cutting installation Source: stream restoration lecture by Karen Firehock

aren Firehock

t method - can be easily e branch with a sharp end bank ground10.

Figure 10: Live cutting installation Source: stream restoration lecture by Karen Firehock

21 Feb. 2015.

3) Fascines: bundles of dormant plants with live and dead brush that root easily. The key points of installation are as follows: ● Tie the brush with twine, 8-10 inches in diameter, and 2-30 feet in length. ● Dig trenches 6-8 inches deep on contour of the stream bank. ● Place the bundles in the trenches. ● Add stakes through and below bundles. ● Cover the fascines with topsoil11. 4. Add informative signs along the trail.

Firehock, Karen. Storm Restoration Lecture. 21 Feb. 2015.

Figure 11: Fascine installation Source: stream restoration lecture by Karen Firehock

Zone 3: Sports Park Problem There are four main problems with Zone 3: 1. Inefficient use of recreational spaces: although the trail is supposed to be a recreational/educational space for the students and visitors, there is a lack of installations that provide such setting. 2. Stormwater drains into path due to uneven topography: the trail was designed to go up the slope into the baseball field, yet this enables stormwater to run right into the path, promoting soil runoff. 3. Erosion and soil depletion along the baseball field hill: there is not a direct access from the field into the parking lot, which encourages visitors and students to run along the hill to get to the parking lot, increasing soil erosion and compacting the ground. 4. Stormwater basin unnoticed: although there is a stormwater basin within the site, it is separated completely from the stream and the path, unseen by visitors or students.

Figure 12: Existing Stormwater basin behind school

Technologies The most cost-friendly and successful retrofit technologies to address these issues are: 1. Bring back adventure and art theme by re-thinking the use of space and open areas and positioning interactive and educational installations. This solution can be addressed through different technologies: ● Sculptured playground → bring sculpture and recreation together to create a natural sculptured playground. The sculptural appeal of the trail can be enhanced with the addition of these “sculptured playgrounds” that children could use as forts. Each classroom could have their own forts that could be built out from different branches deposited along the stream bank (see Appendix Figure 4 for examples) ● Stormwater as art → enhance sculptural appeal of trail and provide interactive spaces where stormwater can be collected and children can learn

and play with it. The Philadelphia water department has some great initiatives, specifically the Herron Playground, for combining playground design and stormwater management12. ● E d u c a t i o n w i t h f o r e s t a t i o n complement trail with green spaces and native plants that can potentially serve as educational gardens and planters for students. Garden Based Education is an organization with great initiatives for educating children through gardens and planters13. 2. Re-think path direction in order to avoid the flow of stormwater into the trail: create a bioswale to retain and clean stormwater draining from the slope with an overflow pipe into the stream. In addition, re-direct trail to circulate topo and avoid sloping. 3. Decrease erosion and soil depletion: Add stairs along the baseball field hill to create a direct access into the parking lot and avoid students and visitors from

climbing the hill. In addition, xeriscaping along the sides of the hill as well to control soil depletion. 4. E n h a n c e s t o r m w a t e r b a s i n : Strengthen the relationship between the trail and the existing basing by providing a direct access to it. If the bioswale becomes more noticeable along the trail, there is even an opportunity to create educational programs for students on stormwater management and bioswale maintenance.

appeal of the area. Xeriscaping is not only useful in terms of water conservation, but it can create an inhabitable outdoor living space rich in vegetation and life, and which requires little to no maintenance, saving money over time13. The aesthetic of the site can also be enhanced by planting climbing vegetation along the fence of the baseball field.

Where to Apply Although these technologies were studied specifically for Zone 3, some of them can be applied along the entire site. For instance, the design of educational and interactive installations is a solution that can be applied along many open, unused areas within the site. The more installations added, the easier it will be to bring back the theme of adventure and art into the trail. In addition, xeriscaping can be applied along the borders of the baseball field to enhance the aesthetic

"Case Study: Greener, Healthier Play: Herron Playground." StormwaterPA. January 1, 2012. Accessed April 27, 2015. http://www.stormwaterpa.org/greener,-healthier-playherron-playground.

"Garden Based Education." Garden Based Education. Januar y 1, 2015. Accessed April 28, 2015. http:// gardenbasededucation.org/. 14

Springer, Lauren. Waterwise Gardening. New York: Prentice Hall Gardening, 1994.

Zone 4: Parking garden Problem The main problem with Zone 4 is the heavy amount of runoff from the driveway behind the main school building that then collects in the far corner of the parking lot. Water runs off of the impervious asphalt driveway, leaving the parking lot in poor condition with deep cracking. This water is left standing on the pavement, posing potential threats for occupant safety as well as trash and sediment buildup. The water then evaporates instead of returning to the local watershed, resulting in a consumptive loss of water for the area. Fur thermore, the cur ve of the driveway directs runoff towards the existing bioswale and a concrete ditch running along the side which empties into the stream. This is problematic due to stormwater contamination from oil, sediment and other pollutants which then enter the stream.

Figure 13: Heavy cracking and water collection in Northwest corner of parking lot

Figure 14: Steep slope of driveway leads to heavy water collection in parking lot. Picture taken one day after heavy storms

Technologies In order to repair these issues, the most cost effective retrofit solutions are to: 1. Reduce the size of the parking lot by approximately 200 ft2 by breaking up and removing asphalt at the Northern end of the lot. The overall impervious surface of the parking lot is reduced as a result. 2. Implement a small bioswale to replace the removed parking lot and collect the runoff from the driveway by adding in biofilter soil, gravel, and sand, and then planting native riparian plants to help retain and filter the water15. â&#x2014;? This bioswale will be mainly focused in the far Northwest corner of the parking lot and will include plants and trees with water retaining properties (Appendix: Table 1). â&#x2014;? The water is able to be filtered and absorbed into the ground before entering the stream. â&#x2014;? T h e b i o s w a l e a n d i n c r e a s e d

vegetation along the driveway also have an added aesthetic benefit, increasing the biodiversity of the area, providing shade, and creating a more pleasing inhabitable garden area. 3. Increase vegetation by using native riparian plants (Appendix: Table 1) to revegetate areas along the driveway and stream so runoff can be filtered and absorbed into the ground before entering the stream. 4. Create a natural drainage ditch will be constructed near the bottom of the driveway with gravel, river rocks and plants to redirect runoff toward the stream and relieve pressure off the parking lot. 5. Provide educational opportunities for children to understand stormwater r u n of f a n d b i o s w a l e ve g e t a t i o n a n d functionality (i.e. painted water drops on pavement to show runoff direction, educational signs, native plant scavenger hunt, and stormwater ar t sculpture in bioswale.

Figure 15: Parking garden retrofit

"Rain Garden Design Templates - Construction & Sequence of Construction." Rain Garden

Design Templates. Accessed April 29, 2015. http://www.lowimpactdevelopment.org/raingarden_design/construction.htm.

cost The cost estimates were calculated based on real market prices. Some of the products and services have well defined prices (like the rocks and stairs, for example). Some prices, however, can vary a lot depending on the environment and on the type of product/service (i.e. living retaining wall price can vary a lot depending on its required strength and on the model of the wall). With that in mind, the calculated price gives the average cost. It can be either cheaper â&#x20AC;&#x201C; with some loss of quality â&#x20AC;&#x201C; or more expensive â&#x20AC;&#x201C; and with high quality products/services. The prices were divided into two categories: price per section (see Appendix: Table 2) and price per priority of product/service (see Appendix: Table 3).

Pollutants The pollution reduction of the site was calculated according to the third volume of the Urban Subwatershed Restoration Manual, using the Simple Method. This method sacrifices precision to provide simplicity to the calculations. It is also based on various assumptions, which might add even more uncertainty to the results. However, even if we assume a large margin of error, it is very clear by the results that the suggested interventions have a huge potential to reduce the pollutants at the site. The current and the future generations of pollutants, and the resulting reduction from the implementation of the proposed stormwater management designs can be seen in Table 4 in the Appendix.

Conclusion In conclusion, we have identified the following five main problems with the stormwater management facilities of the Baker Butler Elementary School Lower Site: 1. Retaining wall failure leading to stream bank erosion and water flow obstruction. 2. The dramatic slope of the trail entry has led to a large amount of sediment runoff along the path. 3. An impervious paved parking lot at the edge of the site, with heavy cracking from water runoff. 4. Erosion of the hill surrounding the baseball field. 5. Lack of sculptures and educational opportunities. In order to address these issues, we suggest a series of retrofits to improve the stormwater fixtures of the site and create a more enjoyable and educational â&#x20AC;&#x153;Art Trailâ&#x20AC;? for the children at Baker Butler Elementary. Through increased vegetation, bioswale construction, trail gradient and soil amendments, stream bank engineering, and added educational art installations, the site can be restored to its full potential, improving both the water quality of the stream and the quality of the trail itself.

Sources "Biological Health of Streams and Rivers of the Rivanna River Watershed." Stream Watch, 2014. Accessed April 27, 2015. http:// streamwatch.org/reports. "Case Study: Greener, Healthier Play: Herron Playground." StormwaterPA. January 1, 2012. Accessed April 27, 2015. h t t p : / / w w w. s to rm w a te r pa . o rg / g re e n e r, healthier-play-herron-playground Center for Watershed Protection. 2007. Urban Stormwater Retrofit Practices Appendices. Manual 3. Chiras, Dan. 2009. "Permeable Pavers: Patios, Walkways, and Driveways Made of Porous Pavement." Mother Earth News. Last modified May 1, 2009. Accessed February 22, 2 0 1 5 . h t t p : / / w w w. m o t h e r e a r t h n e w s . com/green-homes/permeable-paversp o ro u s - pa v e m e n t- z m a z 0 9 a m z r a w. aspx#axzz3Ool78K4h Chollak, T. and P. Rosenfeld. “Guidelines For Landscaping with Compost-Amended Soils”. University of Washington College of Forest Resources, 1998. EPA. 2014. National Stormwater Calculator User ’s Guide. Manual, Washington. D. C.:

Office of Research and Development National Risk Management Research Laboratory. Firehock, Karen. Storm Restoration Lecture. 21 Feb. 2015. "Garden Based Education." Garden Based Education. January 1, 2015. Accessed April 28, 2015. http://gardenbasededucation.org/. ICPI—Interlocking Concrete Pavement Institute. 2014. “Sustainability and Interlocking Concrete Pavements.” “Frequently Asked Questions—permeable pavement.” Accessed March 2, 2015. http://www.icpi.org/ faq/48 "Piedmont Virginia Native Plant Database." Albemarle County Native Plant Search. Accessed April 29, 2015. http://www.albemarle.org/ NativePlants/list.asp?ShowAll=ALL. "Rain Garden Design Templates - Construction & Sequence of Construction." Rain Garden Design Templates. Accessed April 29, 2015. h t t p : / / w w w. l o w i m pa c td e v e l o p m e n t . o rg / raingarden_design/construction.htm. Springer, Lauren. Waterwise Gardening. New York: Prentice Hall Gardening, 1994.

apendix Chart 1: Site Runoff Percentage

Table 1: Native Riparian Plant Palette16

Trees

Shrubs

Plant Maple: Red, Yellow, Striped Birch: River, Yellow Hickory: Shagbark, Pignut, Mockernut White Ash American Beech Magnolia: Cucumber, Sweetbay, Umbrella Sweet Shrub Buttonbush Hazel Alder Silky Dogwood Nodding Beggarticks

Wildflowers Jack-in-the-Pulpit Black Snakeroot Milkweed/Butterfly Weed Grasses

Sedge: Long-Hair, Tussock, Shallow Big Bluestem Grass

Purpose Stream Buffer Stream Buffer Rain Garden/Bioretention Basin Rain Garden/Bioretention Basin Rain Garden/Bioretention Basin Rain Garden/Bioretention Basin Stream Buffer Rain Garden/Bioretention Basin Stream Buffer Rain Garden/Bioretention Basin Stream Buffer Stream Buffer Rain Garden/Bioretention Basin Stream Buffer Rain Garden/Bioretention Basin Rain Garden/Bioretention Basin Rain Garden/Bioretention Basin Stream Buffer Rain Garden/Bioretention Basin Rain Garden/Bioretention Basin

"Piedmont Virginia Native Plant Database." Albemarle County Native Plant Search. Accessed April 29, 2015. http://www. albemarle.org/NativePlants/list.asp?ShowAll=ALL.

Table 2 - Price per section Product/Service Rocks Stone Columns Native plants Soil Amendment Entrance signboard Re-grading the soil Pervious pavement TOTAL Native plants Re-grading stream Living Retaining Fascine Information signs TOTAL Sculptured Re-direct the Enhancing the Basin Climbing vegetation Xeriscaping Stairs

Section 1 Estimated Price per US$9.45/40 lbs. US$79.99 each US$17 sq. ft. US$1-3 sq. ft. US$30 US$1500-2500 US$5-10 sq. ft.

Covered 300 3 (amount) 6,750 4,000 1 1,953.60 2,097.50 $171,034.72 Section 2 9,050 US$17 sq. ft. US$1500-2500 12,340 US$15-30 4,680 US$250 12,340 US$10/unit 50 pieces $227,300 Section 3 US$799.00 1 US$1500-2500 2,040 US$17 sq. ft. 4,000 US$17 sq. ft. 200 US$1-4 sq. ft. US$980

Priority Total estimated 1 to 5 $283.50 4 $239.97 4 $144,750 2 $8,000 3 $30 2 $2,000 4 $15,731.25 4

$153,850 $2,500 $70,200 $250 $500

1 3 1 3 2

$799 $2,000 $68,000 $3,400

2 4 5 3

23,026

$46,052

$980

$121,231

TOTAL Section 4 Native plants

US$17 sq. ft.

200

$3,400

Paint

US$30/gallon

$60

US$4 cu ft.

500

$1,250

Bioswale TOTAL

$4,710

Table 3 - Price per priority Priority 1 2 3 4 5

Total Cost [US$] $224,050 $149,540 $49,452 $40,420 $20,250

Table 4 - Pollutant analysis of the site Pre-Retrofit Pollutant Loading [milligrams] Section Suspended Solids

Fecal Coliform

22.21

5641.3

56.41

157.84

52.15

13248.38

132.48

370.67

61.33

15579.87

155.8

435.9

4 Total

113.85 249.52

0.63 0.63

8.01 758.98 8.01 35228.53

215.04 559.74

586.1 1550.51

Post-Retrofit Pollutant Loading [milligrams/year] Section Suspended Solids

Fecal Coliform

-0.44

338.48

2.82

55.24

2.09

1059.87

13.25

129.74

-1.23

934.79

7.79

152.57

4 Total

-2.28 -1.86

0.18 0.18

3.53 3.53

45.54 2378.68

10.75 34.61

205.13 542.68

Load Reduction of the Retrofit [milligrams/year] Section Suspended Solids

Fecal Coliform

-22.65

-5302.82

-53.59

-102.59

-50.06

-12188.5

-119.24

-240.94

-62.55

-14645.1

-148.01

-283.34

-116.12

-0.45

-4.5

-713.44

-204.29

-380.96

Total

-251.39

-0.45

-4.5

-32849.9

-525.13

-1007.8 29

Figure 1 - Aerial View of Site

Figure 2 - Site Map highlighting Site Features

Table 4 - Pollutant analysis of the site

Thank you