The objective of this project was to study and monitor the implementation of different materials within bioretention ponds and bioswales. The materials observed proved to be useful in understanding the background and purpose of bioswales and their effect on the environment.

There were occasional issues, like the erosion of soil and rock as the swales and ponds were being excavated. Cross-contamination prior to the filling of the swales also proved to be a problem. These errors could be fixed by taking more time and being more cautious. For example, some of the erosion was caused by machinery sitting on the slopes of the swale, which caused unnecessary pressure on the ground. Also, most of the cross-contamination occurred as a result of layering sections at a time. This is easy to solve, as the materials should just be put in until the whole layer is complete.

For my next site, there is a single bioswale. The depth of this facility is approximately 68 inches. Geotextile cloth was placed on the sides, and the areas start with 18 inches of #2 stone (same crushed stone material as before, but significantly larger than #57 stone). Next was 18 inches of #57 stone with a 6” perforated PVC subdrain in the middle of the layer, followed by 4” of #7 stone, 4” of coarse sand, and 24 inches of BSM. In four separate spots along the sloped swale, approximately 4” of topsoil was added for the aforementioned check dams.

At this site, all three micro-bioretentions had the same make-up. The cross-section shows that the depth of each area was 5 foot, 7 inches. Non-woven geotextile cloth was placed on the sides and the areas start with 32 inches of the #57 stone, where a 4” perforated PVC pipe was double wrapped in a galvanized hardware cloth and surrounded by 4 more inches of the #57 stone. Next was 4” of #9 stone (same crushed stone material, but smaller diameter), followed by 2 feet of BSM, with 1 ½” of mulch and 1 ½” of decorative landscaping stone to top it off.’

For my next site, the three bioswales had the same make-up, with one difference of differing amounts of BSM. The single micro-bioretention had its own unique make-up. Bioswales B, C, and D each had a depth of 68 inches, 44 inches, and 68 inches, respectively. Geotextile cloth was placed on the sides, and the areas start with 12 inches of #57 stone with a 4” perforated PVC pipe in the middle of the layer. Next was 4” of #7 stone (similar to #9 but a little larger in diameter), followed by 4” of coarse sand and 24-48 inches of BSM. Shown in figure 3, area A had a depth of 53 inches. Non-woven geotextile cloth was placed on the sides and the areas start with 18 inches of #57 stone with a 6” perforated PVC subdrain in the middle of the layer. Next was 4” of #7 stone, followed by 4” of coarse sand, 24 inches of BSM, and 3” of mulch.

The construction of multiple bioswales and bioretention ponds on three different sites were observed.

The first site observed was on the future location of a Starbucks, which included three separate micro-bioretention areas. Micro-bioretention area #1 consisted of a 71’x12’ area with an observation well, two cleanouts, an outlet structure, and three ripraps. Micro-bioretention area #2 consisted of an L-shaped 23’x17’ area with an observation well, a cleanout, an outlet structure, and two ripraps. Micro-bioretention area #3 consisted of a 43’x4’ area with an observation well, a cleanout, an outlet structure, and one riprap.

The second site observed was on the edges of a roundabout, which included three bioswales and a micro-bioretention. The micro-bioretention (area A) consisted of a 48’x37’ area with an observation well and three cleanouts. Bioswale B consisted of a 154’x8’ area with two cleanouts and one riprap. Bioswale C consisted of a 41’ long area with a varied width between 2’ and 8’ with one cleanout. Bioswale D consisted of a 131’ long area with a varied width between 3’ and 7’with three cleanouts.

The third and final site observed was on the edge of a major highway, which included just one bioswale. The bioswale consisted of a sloped 72’x8’ area with an observation well and one cleanout. As this swale was sloped, it required a special addition of three concrete separator walls that prevented pre-determined cross-contamination and four check dams that help prevent erosion by reducing the speed of water flow down the bioswale.

The water that is running through streets and sidewalks is far below the sought quality for our modern-day world. Bioretention ponds and bioswales are starting to be applied all over the country in order to assist in the cleaning of the stormwater, before it flows out to major tributaries and eventually the oceans. The work conducted with Environmental Consulting Services (ECS) has revealed the importance of these stormwater management facilities and the materials found within each pond or swale. Each facility is a different size and shape. This and the location determine which materials and how much of each material is needed for the facilities. Bioswales, which are sloped to help move water through the system efficiently, are the main focus, although bioretention ponds, which are depressed vegetated areas that only capture and store the runoff, are just as important and will be a minor part of this project as well, as they usually work in combination with each other. Micro-bioretention ponds, which will be referenced are just smaller scale versions of a normal bioretention pond that would be normally found. There are many different features found in these facilities. An observation well is used to observe the changes in the levels of groundwater over a period of time, or during a scheduled pumping test. Cleanouts are structures that allow access to a storm drain for cleaning. Outlet structures are connections from the bioswale to main sewer pipes. Lastly, ripraps are structures to help against erosion and add an extra filter to the stormwater that will flow into the bioswale.