Home Blog Page 12

Rain Barrel Event Combines Fun and Education

Figure 1. Rain barrels get a creative makeover before going home with their new owners at the Rain Barrels and Beer event in Anderson, South Carolina.

Sustainability Through Innovation
This article is part of Environmental Connection’s mission to help grow the industry by promoting innovative research, products and technology that meet industry needs through more sustainable approaches. Articles in future issues will continue to provide multiple perspectives to promote ongoing efforts to protect natural resources.

Since 1937, Soil and Water Conservation Districts have diligently worked to meet the needs of local landowners while also providing education and activities that help to advance resource conservation within the county, state and around the country. The South Carolina Conservation District Association represents the 46 Soil and Water Conservation Districts. These 46 districts make immeasurable impacts on the quality of land, water and related natural resources.

One district in Anderson County, South Carolina hosts an annual event that draws people from around the state to participate. Anderson Soil and Water Conservation District (ASWCD) is charged with meeting basic land, water and other natural resource problems locally. ASWCD is a subdivision of the South Carolina Department of Natural Resources. Each year ASWCD, in partnership with Anderson Regional Joint Water System (ARJWS), hosts an event called “Barrels and Beer” at local breweries in Anderson County. The 2023 Barrels and Beer event will be the event’s 5th anniversary.

The event provides environmental education and fun activities that teach community members how to become environmental stewards in their own backyards. Proceeds from the event are given back to the community through an Environmental Stewardship Mini-Grant program that awards up to $1,000 grants to people, businesses or schools to assist with projects related to protecting the environment, sustainable farming or environmental outreach and education.

To prepare for the event, 55-gallon (100-liter) rain barrels are donated to ASWCD each year from various businesses that have extra food grade barrels. The educational aspect of this event provides participants a unique viewpoint of how beers are brewed using locally sourced waters and the many different groups that work to protect these waters such as ARJWS, Lake Hartwell Partners for Clean Water, the Natural Resource Conservation Service, Clemson Extension, Upstate Forever, Savannah River Keeper and other groups.

One of the main attractions in Anderson County is its beautiful lakes, streams and waterways. Lake Hartwell can be seen while driving through the county and covers over 56,000 acres (22,662 hectares) and 962 miles (15,490 km) of shoreline stretching over South Carolina and Georgia. This lake provides the county with its drinking water and is one of the region’s largest man-made lakes. Participants at Barrels and Beer hear from expert guest speakers during educational sessions. As participants learn, they are also creating their own art masterpieces by painting their rain barrels (Figure 1) to make them more aesthetically pleasing. ASWCD believes that tying education, enjoyment and social together creates an atmosphere that helps to strengthen the bonds within the conservation family.

The 2018 Journal of Environmental Management states “…the effectiveness of urban stormwater management practices on local water quality is dependent on adoption rates reaching a critical mass.”1 Urban areas have seen an increase in impervious surfaces such as roads, rooftops and sidewalks that lead to more stormwater runoff, which means a higher chance for pollutants to enter waterways and increased flooding. Being mindful of these impacts directs us to think about the ways individuals can make a difference. Rainwater harvesting, or bioretention, is defined as the collection and storage of rainwater that runs off rooftops, parks, roads and open grounds.2 Rainwater harvesting allows homeowners to save water between rain events and prepare for times of drought.

Approximately 33 rain barrels are sold and installed at Anderson County households from ASWCD’s Barrels and Beer event each year. Based on the number of rain barrels sold each year and using the average home size in South Carolina, an estimate of the amount of rainfall collected by participants each year can be formed. The average roof size of a standard home is around 1,000 square feet (92.903 square meters). If a 1-inch storm generates 623 gallons (2.36 cubic meters) of runoff on an average size roof according to Clemson Carolina Clear’s “Rainwater Harvesting for Homeowners” manual, then an estimated 20,559 gallons (77.82 cubic meters) of stormwater is collected each year from event participants from a single 1-inch rainfall event.3

The impact that this event has on our community in Anderson County makes a huge difference for conservation. Not only does it spark interest in stormwater management and conservation practices, but it also gives back to the community through the Environmental Stewardship Mini-Grants to continue the legacy of locally led conservation efforts. 

References:

  1. Gao Y, Church SP, Peel S, et al. Public Perception Towards River and Water Conservation Practices: Opportunities for Implementing Urban Stormwater Management Practices. Journal of Environmental Management. 2018. 223:478-488.
  2. Ibid.
  3. Giacalone K, Joyner D, Bishop M, et al. Rainwater Harvesting for Homeowners. Clemson University Carolina Clear. 2011.

About the Expert

Anaston Porter is the Anderson Soil and Water Conservation District Education and Outreach Coordinator.

By the Numbers: SC Conservation Districts’ Impact
The South Carolina Conservation District Association’s 46 Soil and Water Conservation Districts work throughout the year to promote environmental education and support conservation efforts. Highlights of the 2021 efforts include:

More than 20,000 adults educated on varying conservation topics including Farm Bill programs, pollinator promotion, stormwater mitigation, invasive species control, prescribed fire, water quality and conservation, habitat restoration and land easements.

Over 4,000 acres (1,600 hectares) statewide impacted by conservation rental equipment available through conservation districts (no-till drills, prescribed fire equipment, feral hog traps, etc.).

30,000 students were reached by conservation district youth oriented programs such as school gardening, seed libraries, SC Envirothon, Arbor Day and Earth Day events, stormwater education, scholarships, and conservation related contests in 2021.

You Shouldn’t GROW it Alone

Trying to grow your business alone can be risky and unproductive because no one person or organization has all the necessary answers, connections and resources needed for growth. People and organizations outside of your company and industry who share the same customers can help you grow your business. There are even circumstances in which your competitors can be smart partners to help both of you reach new markets, develop new products and tap into additional talent.

A market map is a powerful, easy-to-use business growth tool that can help determine how and with whom we should develop smart partnerships. Updating your map quarterly helps you stay on track in continually evolving markets. Once you’ve completed your first map it’s fast, easy and fun to update.

The tool allows you to map all the players in your marketplace, shows where and with whom you spend money, lays out the competitive landscape and identifies the supply chain and communication channels. It is a snapshot of your current strategy and a potential roadmap for future growth. There are 10 simple steps to create a market map.

Start with a flip-chart sized piece of paper, colored sticky notes and your team. If you can’t meet in person, use a free service like Zoom, and use their digital white board and sticky notes to build the map. In the middle of the of the sheet place a sticky note with your company name on it.

On the left side of the paper make a column entitled “customers” and from top to bottom list all your current customers and qualified prospects. If there are too many to list, you can use segment names like civil engineers or residential developers, and then list individual names under each segment.

Make a column next to your customers called “channels” and list all the individuals or companies that can sell, resell or refer business to you or enhance opportunities with current customers.

Draw the connections using a line between your company, channels and customers. The more connections you identify, the stronger your network for growth. Fewer lines drawn identifies a path to new relationships and opportunities. Assign people to those qualified opportunities ASAP.

On the right side of the sheet make a column for all the “suppliers and partners” and list the companies with whom you work and those you don’t. Strategic business plans include suppliers and partners who should be some of your greatest advocates, advisors and business developers.

Draw a line between your company and suppliers with whom you do business. Leverage those current relationships for stronger growth and connect with those qualified players you have no relationships with but may provide mutually beneficial opportunities.

Create a column with all your competitors, list as many as you can as you need to be aware of everybody — don’t underestimate anyone.

Draw lines from your competitors to your customers, prospects and channels. You’re looking for as little overlap as possible here. Fewer connections from competitors mean you hold a unique position. More connections mean you are more likely to be selected on price.

At the top of the page list all the trade or business associations, media, institutes, networking groups and alliances that are relevant to your company and draw a line from your company to those with whom you have relationships. Strengthen existing relationships and forge new connections to generate new opportunities.

Put a dollar sign on the relationships where you make and spend money. These are the places you have greatest power. The areas you don’t spend time, money or resources are your weak areas that could present some of your greatest possibilities to grow. 

About the Expert

Judith M. Guido is the chairwoman and founder of Guido & Associates, a business management consulting firm in the erosion control and green industry. Guido can be reached at 818.800.0135 or judy@guidoassoc.com.

Covering the Soil: What’s Best?

Figure 1. Final condition of the three plots where vegetation established well, photographed in April 2022. Shown from left to right are juniper, vetiver and fescue. Photo credit: Frances O’Donnell.

Many of us have heard the mantra about soil erosion prevention that goes something like: “It’s the cover, dummy!” Many studies have shown that covering up the soil with something can reduce erosion by more than 90%, but what should that “something” be? There are lots of options and a few of these have been the focus of recent studies on erosion and vegetation establishment under a wide variety of conditions.

Establishing vegetation under semiarid conditions is very challenging, so Leger et al. (2022) conducted a study to test three different covers for their ability to improve soil and foster native plant establishment.1

The site was a degraded rangeland in the Sonoran Desert of Arizona. The treatments included a control with no cover and a cover made of intact mesquite branches that provided approximately 60–70% shade with about 40% contact with the soil. In addition, two more treatments included the mesquite branches with either 3 or 6 cm of yard waste/dairy manure compost underneath. These four treatments were all seeded with a native perennial grass, and an additional control treatment with no seeding was included.

Overall, the best treatment for plant establishment was the mesquite branches alone, especially for grasses and forbs. Shrubs were more abundant in the control (seeded or unseeded) and mesquite branch plots. Adding 3 cm of compost under the mesquite branches somewhat reduced plant establishment, but the 6 cm addition had a clear negative impact. The authors speculated that the relatively light rainfall events during the study was intercepted by the compost and did not reach the soil to benefit germinating or establishing plants. The branches passed most of the rain through to the soil. The authors noted that the compost appeared to inhibit germination of the native plant seeds present in the soil as there were a wider variety of plants under the branch mulch.

Rocks are often present at the soil surface, particularly at disturbed sites, and their effect on soil erosion has been the subject of considerable study. Quantifying the effects of both rock size and amount of cover was the objective of a recent experiment in a rainfall simulator.2 Eight different rock sizes (0.7 cm–35 cm) were placed on a soil at four cover rates (15%, 30%, 45%, 60%) followed by 60 mm h-1 rainfall for 45 minutes. Runoff was collected at the bottom of the 2 m box (15° slope) and the amount of runoff and erosion determined. An additional rainfall event was run to determine differences in dry versus wet soils. The goal of this study was to establish statistical relationships between rock size and cover to be used for modelling erosion in areas with different rock covers. There was a division of results among rock sizes, with those less than 12 cm reducing erosion and increasing runoff with increasing cover. Those greater than 12 cm increased erosion and runoff with increasing cover up to 45%, with a slight decrease at 60%, especially for the wet soil where rills were evident.

In temperate, humid environments the establishment of vegetation on steep slope is often a race between plant germination and growth and erosion from frequent rainfall events. Asima et al. (2022) tested six different plant types for establishment and erosion prevention over a two year period in the Piedmont of Alabama, USA.3 Two of the plant types, maidenhair fern and hairy vetch, did not establish well and were replaced with juniper and fescue and switchgrass. The remaining plants were fescue, vetiver grass and juniper alone (Figure 1). The vetiver and juniper were planted from potted plants while the fescue and switchgrass were established from seed. The plots were not replicated so statistical analyses are not possible, but there were no clear differences in erosion rates. However, the vetiver grass had far more and deeper roots than the other species, suggesting it was likely to stabilize slopes better. It was also more competitive against weeds, which were a persistent problem in the other vegetation types. 

References:

Leger, A. M., K. R. Ball, S. J. Rathke, J. C. Blankinship. 2022. Mulch more so than compost improves soil health to reestablish vegetation in a semiarid rangeland. Restoration Ecology 30 (6): e13698. doi: 10.1111/rec.13698.

Li, X., S. Fu, Y. Hu, B. Liu. 2022. Effects of rock fragment coverage on soil erosion: Differ among rock fragment sizes? Catena 214: 106248. doi.org/10.1016/j.catena.2022.106248.

Asima, H., V. Niedzinski, F. C. O’Donnell, and J. Montgomery. 2022. Comparison of vegetation types for prevention of erosion and shallow slope failure on steep slopes in the southeastern USA. Land 11: 1739. doi.org/10.3390/land11101739.

About the Expert

Rich McLaughlin, Ph.D., received a B.S. in natural resource management at Virginia Tech and studied soils and soil chemistry at Purdue University for his master’s degree and doctoral degree. He is a professor and extension specialist in the Soil Science Department at North Carolina State University in Raleigh, North Carolina, specializing in erosion, sediment and turbidity control.

Turning Mining Spoils into Soil that Sustains Pastures

Figure 1. Floating wetland plants used for bioremediation.

An unavoidable aspect of coal mining is the accumulation and piling of overburden — the rock or soil layer that needs to be removed in order to access the ore being mined. The removal of topsoil increases the difficulty and cost of rehabilitating mining sites.

In Queensland, Australia, a partnership of companies that includes a soil remediation contractor, horticultural consultant, mining industry consultant and an environmental consultant has developed a process to turn coal mine overburden into viable topsoil and pasture. Not only does the sustainable process improve reclamation of mining sites, but the first project resulted in a significant emission reduction from reduced truck transport of material.

A chance conversation with construction industry colleagues at a networking event led to the innovative approach. SoilCyclers had been turning subsoil into topsoil for many years, so the discussion about topsoil deficits on mine sites and a mining industry consultant’s observation of plants growing in the overburden inspired the first endeavor.

The project began with a loader digging a few metres into 20 different overburden stockpiles across a 30-kilometer (18.64-mile) length of the site to take samples. Samples were taken of materials that had not been exposed to rainfall to ensure that amelioration would address deficits in the worst material.

SoilCyclers were confident about their ability to make topsoil, but not confident about the project’s success without some short-term irrigation to ensure germination. The project was expanded to include bioremediation of mine water using floating wetlands and growing of salt tolerant cattle pasture grasses in ameliorated coal mine overburden using partially treated salty mine void water. The joint venture partnership secured a Queensland Government collaboration grant through METS Ignited to cover half the project costs, with the remaining 50% funded by their client.

Figure 2. Trommel screen turning overburden into topsoil.

The team scoured the site looking at grasses growing in drains that carried salty water and conducted germination trials to develop a proprietary salt-tolerant pasture grass mix. Floating wetlands (Figure 1) were constructed onsite for bioremediation of the pit water, and two of the most challenging types of overburden were chosen for the trial. Overburden was ameliorated through a trommel screen (Figure 2) with locally sourced ameliorants by changing the physical, biological and chemical properties.

Multiple plots were grown to demonstrate day watering and night watering of full salt, 10,000 EC of straight mine void pit water with electrical conductivity (EC) values ranging between 10,000 and 13,000 microsiemens per centimeter (µS/cm) and partially treated 5,000 EC water ranging between 5,000 to 6,000 µS/cm EC on ameliorated permian overburden, ameliorated tertiary overburden, the site’s ameliorated topsoil and unameliorated topsoil samples.

Figure 3. Salt tolerant pasture grasses growing in topsoil manufactured from overburden six weeks post planting.

The trial was an outstanding success, with the partially treated 5,000 EC water irrigating a salt-tolerant seed mix at night on topsoil made from ameliorated permian and tertiary overburden growing full grass coverage in six weeks (Figure 3). The topsoil made from overburden even outperformed the site’s existing ameliorated topsoil.

Watering was stopped at six weeks, and the plots were monitored throughout a drought, where they remained well established with full grass coverage and flourished again following rainfall more than a year later.

Since the project was completed, SoilCyclers set their sights on other mine wastes. Tailings, which are contaminated slurry left over from processing are usually stored forever in tailings dams. In South America, the proprietary process was used to turn tailings from a copper mine into topsoil that now grows radishes. The project was undertaken as part of a consortium of Australian and European businesses who were Top 10 finalists in the BHP Tailings Challenge. 

About the Expert

Alison Price is the founder and managing director of SoilCyclers, an Australian soil amelioration and remediation contractor.

About the Project Partnership

The Ensham Mine Spoil Remediation Project was handled by a joint venture partnership comprised of SoilCyclers, Innovate Enviro and Cammel Consulting. Aaron Ashlin from Hortus Group served as the soil scientist. The project was jointly funded by the Queensland Government, METS Ignited and the client, Idemitsu.

Constructed Wetlands: Positive and Negative Impacts

Figure 1. The dry detention basin monitored in the Humphrey study, showing the area near the outlet with wetland characteristics in the foreground and the higher, dryer portion in the distance. Photo credit: Charles Humphrey.

Runoff from urban areas was first recognized as a problem for receiving waters in terms of too much volume in too short of a time period. The solution was to detain the water and release it more slowly. Then it became clear that contaminants in the runoff, including heavy metals and nutrients, were also a problem. One of the solutions was to construct wetlands to both detain the water and treat it by removing some of the contaminants. Two recent studies investigated how well these types of devices perform, with very different conclusions.

Dry detention basins (DB) are constructed to contain stormwater runoff, release it in a controlled manner and drain completely between storm events. The first study evaluated a well-established DB for its ability to retain nitrogen, a common pollutant, over a one-year period.1 The DB drained a 15 ha area of Greenville, NC, USA with a 30% impervious cover. The DB itself was intended to be dry with a grass cover, but over time (10 years), a wet area was formed near the inlet where wetland plants such as Typha spp. (cattails) became established on 40% of the area (Figure 1). Water levels were monitored using stilling wells and loggers, and water quality was monitored at the inlet and outlet during eight storm events. During the warm months, outflow was reduced by 33%, but during the cool season outflow was increased by 18% — likely due to groundwater inputs. Shallow groundwater tables typically are higher in winter in this region. The concentration of total N was reduced in the DB by an average of 21%, although this was highly variable much like the flows. The average total N load was reduced by an average of 52% over the eight storms. The authors suggested that the mix nature of the DB, with some wetland characteristics, may have improved TN reduction from the 10% credit that the state allows for DBs.

While it has been known that constructed wetlands can be a source of greenhouse gases, a recent study suggests that contribution may be much greater than previous studies have indicated.2 The authors sought to quantify the release of three greenhouse gases (CO2, CH4, N2O) from four constructed wetlands in the Melbourne, Australia area. In particular, they wanted to measure releases from both diffusion and ebullition (bubbles), the latter often not being included in many similar studies. Emissions by diffusion were estimated using floating chambers and measuring gas concentrations over 5–10 minutes, while funnels anchored to the bottom were used to collect “bubbles” over the whole week. Measurements were taken both day and night over a four-week period in March. Bottom samples were taken during the first and last week to characterize the microbial communities. Surprisingly, there were no differences in emissions between day and night and little correlation between emissions and water temperature. Higher dissolved oxygen increased CH4 (methane) release while higher turbidity had the opposite effect. Gas bubbles were the dominant source of CH4 but were a minor part of CO2 and N2O releases. There were some relationships between the microbial communities and gas emissions, such as higher abundance of species involved in methane oxidation and lower methane emission. Overall, the inclusion of gas bubbles along with diffusion losses was calculated to increase greenhouse gas emissions from constructed wetlands by threefold compared to other studies. 

References

Humphrey, C.P., Jr.; Iverson, G.; Nolan, M. 2022. Nitrogen treatment by a dry detention basin with stormwater wetland characteristics. Hydrology 9, 85. https://doi.org/10.3390/hydrology9050085.

Bonetti, G., S. M. Trevathan-Tackett, N. Hebert, P. E. Carnell, and P. I. Macreadie. 2021. Microbial community dynamics behind major release of methane in constructed wetlands. Applied Soil Ecology 167, 104163. https://doi.org/10.1016/j.apsoil.2021.104163.

About the Expert

Rich McLaughlin, Ph.D., received a B.S. in natural resource management at Virginia Tech and studied soils and soil chemistry at Purdue University for his master’s degree and doctoral degree. He is a professor and extension specialist in the Soil Science Department at North Carolina State University in Raleigh, North Carolina, specializing in erosion, sediment and turbidity control.

Research Preview: The Development of a Sediment Control Approved Products List

Figure 1. The Texas A&M Transportation Institute’s Sediment and Erosion Control Laboratory is the site of a new sediment control device testing program.

The Texas A&M Transportation Institute (TTI) has more than three decades of evaluating the performance of erosion control products. These products include rolled erosion control products (RECPs) and hydraulically applied products (HECPs). The results provide the data for the Texas Department of Transportation (TxDOT) Approved Product List for erosion control products. While this program has ensured the use of the most appropriate erosion control products, sediment control devices (SCDs) have not been included in the process. However, beginning in fall 2023, an approval process for SCDs will be initiated for TxDOT.

Background

The Environmental Protection Agency guidance document “National Management Measure to Control Nonpoint Source Pollution from Urban Areas” requires all construction site activities to reduce the amount of sediment generated and reduce the off-site transport of sediment and construction-related chemicals.1 While there are several pollutants of concern (oils, gasoline, degreasers, paints, etc.), sediment from construction sites is by far the largest pollutant source. Eroded sediment from construction sites causes many problems, including traffic safety issues, adverse impacts on water quality as well as decreased capacity of reservoirs and streams, resulting in possible flooding.

SCDs are used on construction sites to retain sediment and prevent stormwater from adversely affecting adjacent waterways. SCDs include wattles, sediment logs, filter dams and inlet protection devices. These products are designed to be installed for specific applications such as curb inlets, drop inlets, perimeter protection, etc. However, there is not a scientifically sound, repeatable testing methodology that replicates field conditions to test and determine SCD performance.

Researchers at TTI’s Sediment and Erosion Control Laboratory (Figures 1 and 2) are in the process of developing a formal testing protocol/facility, test apparatus and future thresholds for a performance based SCD testing program that will assist the designer/engineer in selecting the most effective sediment control best management practice. The test apparatus and test protocol will include, but is not limited to drop inlets, curb/gutter, dewatering bags, and turbidity barriers.

Implementation

TxDOT construction projects are required by state and federal regulations to implement sediment control measures called best management practices (BMPs) to protect water quality during construction. Currently, however, there are no TxDOT-established minimum performance requirements for sediment control BMPs. No guidance exists to provide quantitative information to TxDOT personnel on the efficacy of these SCDs or information documenting under what conditions they will perform adequately.

To meet federal guidelines and assist the TxDOT’s environmental quality requirements, TTI is working to develop a formal testing protocol for the evaluation of SCDs that can be implemented as an SCD performance evaluation program. An SCD performance evaluation program will allow TxDOT division and district planners and engineers to select the most effective sediment control devices specific to site conditions and project needs. TTI will also produce an Approved Product List for all SCDs used by TxDOT on Texas roadsides. TTI recommends incorporating the SCD APL in the current process for listing approved erosion control products.

Figure 2. The lab has tested erosion control products including rolled erosion control products and hydraulically applied products for the transportation industry.

Research Plan

TTI has assembled a multi-disciplinary team with extensive experience in erosion and sediment control and storm water management. The group assembled to complete this two-year project is also skilled in planning, developing and managing test protocols and product testing. The work plan of the project is divided into six tasks — with the findings of each task providing input to the next task.

The tasks include:

  1. Project management: TTI is documenting all research findings from this project, consolidating data, submitting required reports, and attending project progress meetings as scheduled by and in conjunction with TxDOT.
  2. Document state-of-the-practice: TTI is assessing the state-of-the-practice and identifying key metrics in the performance evaluation of SCDs through a detailed review of the literature and structured interviews with TxDOT well as other DOTs and other stakeholders.
  3. Assess existing SCD testing protocol: In conjunction with task 2, TTI is evaluating existing SCD test methodology. Components that meet the testing goals of TXDOT and are effective for gathering data and developing an effective test method will be used to enhance the development of the TTI/TxDOT test apparatus and testing protocol.
  4. Enhance TxDOT/TTI SCD testing system: TTI has performed previous work with sediment control devices installed in high flow channels and is now placing specific focus on expanding and formalizing its SCD testing system to evaluate additional SCDs used in different applications, including, but not limited to drop inlets, curb/gutter, dewatering bags and turbidity barriers to the proposed test protocol.
  5. Develop test protocol, calibrate SCD testing system, test SCDs: TTI is developing an SCD data testing and collection plan. Once this plan is finalized, the system will be calibrated, and product testing will begin. TxDOT approval of the test protocol and test methods, including evaluating calibration and preliminary data results will be conducted prior to the start of any formal SCD testing.
  6. Incorporate SCD testing results in an Approved Product List for erosion control products: TTI is revising and updating TxDOT’s process for listing approved erosion control products to include approved SCDs.

Formal proprietary testing and approved products listing of SCD products that meet minimum performance thresholds will begin once this project is complete in August 2023. 

Reference

  1. National Management Measures to Control Nonpoint Source Pollution from Urban Areas, November 2005, EPA-841-B-05-004.

For more information, contact:

  • Jett McFalls, project supervisor, Texas A&M Transportation Institute, Environment & Planning. j-mcfalls@tti.tamu.edu or 1.979.317.2801.
  • Derrold Foster, SEC lab manager, Texas A&M Transportation Institute, Environment & Planning. d-foster@tti.tamu.edu or 1.979.317.2242

Keep It Covered to Control Erosion

Figure 1. Raindrop splash and displacement of soil particles. Source: USDA Natural Resources Conservation Service.

If a construction site is “out of control” from an erosion and sediment control standpoint, those in charge should review the Five Pillars of Construction Stormwater Management [see “Five Pillars,” page 15]. These pillars — manage communication, work, water, erosion and sediment — are now widely distributed throughout the construction stormwater management world and are easily found with an internet search. Let’s assume that you can get the first three pillars — communication, work and water — fixed and you are ready to conquer the fourth pillar, erosion.

In order to control erosion on a construction site, you must first understand the erosion process.

Rainfall and the surface runoff of rainfall produces four main types of erosion on a construction site:

  • Splash erosion occurs when the raindrop impacts the bare soil surface and dislodges soil particles (Figure 1).
  • Sheet erosion occurs either after the surface of the soil is saturated or the rainfall exceeds the infiltration rate of the soil. Then the soil detached by splash erosion and the additional soil particles detached by runoff/overland flow move downslope. Splash and sheet erosion are sometimes referred to as interrill erosion.
  • Rill erosion occurs when the sheet flow concentrates and causes small rills with a depth of about 1 inch (2.5-cm), further eroding the soil surface.
  • Gully erosion occurs when runoff water in a rill detaches more soil and deepens and/or widens the channel to a significant size. There is no universally recognized depth when a rill becomes a gully.

So, if we can control erosion, there is much less sediment to deal with on a construction site. And the best way to control erosion is to stop the processes of splash and sheet (interrill) erosion.

In order to do this, we should always look for ways to:

  • Minimize the amount of bare soil exposed to the environment by phasing work and limiting vegetation clearing.
  • Minimize the time that bare soil is exposed to the environment by covering the surface of the bare soil and vegetating each are as soon as the final surface is achieved.

When you minimize erosion, capturing sediment, also known as the fifth pillar, becomes easier.

Figure 2. Incorporating lime and fertilizer into soil through tilling supports better root development and faster coverage of bare areas. Source: Michael Perez, Auburn University.

Establishing Vegetation

If areas are already bare, how can you establish vegetation to control erosion? In order to establish permanent vegetation and ensure that it is long-lived, the root zone in the soil must be “right.” That is, the pH must be within an acceptable range, and the plant community must have access to the plant nutrients needed for a particular species to thrive.

So, what if your soil test calls for agricultural lime and plant nutrients, such as nitrogen, phosphorus and potassium fertilizer? How do you ensure these soil amendments are incorporated the best way for the roots?

Whenever possible (generally slopes 3:1 or flatter), lime and fertilizer should each be applied in split applications crossing each other to ensure uniformity. Once applied, the soil amendments should be incorporated through heavy discing or rototilling (Figure 2) to the depth needed to create an adequate zone for root development, which is generally 6 to 8 inches (15 to 20 cm). Incorporation of lime increases pH at a much faster rate in the root zone than surface-spread lime with no incorporation. I’m told that surface-applied lime slowly moves down into the soil at a rate of only one-fourth inch per year.

So, whenever possible incorporate your lime and fertilizer, and the vegetation will thank you by being there for years.

Once the sodding or seeding and mulching are properly completed, the area needs moisture for the seed or plants to thrive and cover the area. Your site could be getting into the time of year when soils can be dry due to hot and/or windy conditions, and you can have several days without rain. So, to encourage germination of seed and growth of grass or sod, we turn to irrigation to overcome dry soil and drought conditions. The question then is “how much water is needed?” And the answer is probably more than you thought.

Newly seeded areas need water for germination and then water for growth. Newly sodded areas need immediate water for sod survival, and then frequent watering until the sod has formed a good root system. Follow quality guidance documents from sources such as extension services to determine how much water is needed. One inch of water would probably be a minimum for initial watering. That equates to about 27,154 gallons of water for an acre (254,000 liters per hectare). Can you do that with a hydroseeder? Maybe, but it would take a large tank hydroseeder multiple loads for an acre or hectare. After the initial wetting, newly seeded and sodded areas will need additional water daily or maybe multiple times per day until germination or root development. The other issue is that the water needs to infiltrate and not run off. So, it would need to be gradually and evenly applied, which is hard to do with a hydroseeder. To do it right means using a properly designed irrigation system.

You can use a hydroseeder to apply water on small areas, but if large areas need water, plan for an irrigation system. As the spring and summer days pass by, it becomes increasingly important to care for the seeding or sodding project as growing days become fewer to establish the desired vegetative cover.

If you minimize erosion in every way possible, sediment control is much easier.

The bottom line is “Keep the Soil Covered.” 

About the Expert

Perry L. Oakes, PE is currently Alabama’s Erosion and Sediment Control Program Coordinator for the Alabama Soil and Water Conservation Committee. Perry was formerly the State Conservation Engineer for USDA-Natural Resources Conservation Service in Alabama.

Five Pillars Provides Erosion and Sediment Control Framework for Construction Sites

The Alabama Department of Transportation pioneered an innovative approach to better management of erosion and sediment on large construction sites. The approach focuses on identification and implementation of effective best management practices that make practical and economic sense for the project versus simply checking items off a compliance checklist. The Five Pillars of Construction Stormwater Management are to be implemented in order of effectiveness and economy. They include the following actions, in order:

  1. Manage communication.
  2. Manage work.
  3. Manage water.
  4. Manage erosion.
  5. Manage sediment.

Reference

Fagan B. The Five Pillars of Construction Stormwater Management. TR News No.328 July-August 2020, pp. 38-41. https://onlinepubs.trb.org/onlinepubs/trnews/trnews328Pillars.pdf.

Customers are not Companies. They’re People!

The key to success is understanding that your customers are living, breathing humans versus a company that is nothing more than a designated legal entity such as an LLC or an S corporation. It is our customers’ humanness that determines why, what, how, where and when they buy products and services from us or our competitors. The legal document that defines the business entity sits silently in the database or file drawer of a government office and gives us no insight into our customers.

So, what do we need to know about customers? First, identify your core customer — the person or group whose buying behavior results in optimal profit. Then, find others with a similar customer profile. The rest of your customers are more than likely draining profits and energy out of you and your team. Increase their pricing so they are buying at an optimal profit or introduce them to your competition.

Next, realize there is usually more than one individual or group included in the decision-making process, and each has a specific job to perform, gains they wish to secure, and pains they must avoid that affect and influence their decisions. It is up to you to understand which jobs, gains, pains and outcomes have been prioritized and align them with your solutions.

There are distinct types of key customers that exist in the buying process with each having specific roles. The six primary customer profile types you’ll most often encounter are the influencers, recommenders, economic buyers, decision-makers, end users and saboteurs.

The influencers are the individuals or groups whose opinions decision-makers may listen to, even if informally. They have the potential to sway a decision one way or the other. I have had clients who underestimated these folks and ended up on the short end of the deal. Next are the recommenders whose job is to conduct the search for a particular product, service or team, and make a formal recommendation for or against it. Know what motivates these folks and what priorities are driving their recommendations.

Economic buyers are the individuals or group who control the investment and make the actual purchase. Economic buyers may also include a third-party management group or government employees. It’s vital you satisfy the financial criteria and priorities of the folks who write the check. Cost and return on their investment are always going to be key drivers for them.

Decision-makers are the person or group ultimately responsible for making the final choice of whom is awarded the win. These customers have the authority over the investment and hold the greatest power.

But let’s not forget two more important customers who yield power, the end user who is the beneficiary of the product, service and team that supports them. And finally, the individual or group most likely to blindside you, the saboteurs. These are the folks who can obstruct or derail the process of evaluating and purchasing your products while tainting your team. Remember, customers are more than an anonymous business — get to know who is who to ensure success. 

Judith M. Guido is the chairwoman and founder of Guido & Associates, a business management consulting firm in the erosion control and green industry. Guido can be reached at 818.800.0135 or judy@guidoassoc.com.

The Intersection of Erosion Control and Wildlife

Figure 2. Training contractors about wildlife in the jobsite area is an important component of protecting endangered species.

Early erosion control focused on modifying agricultural practices and plantings, such as kudzu. Early construction erosion and sediment control techniques focused on hay bales and silt fence while modifying the agriculture practices developed by the USDA Soil Conservation Service (formerly the Erosion Control Service, now the Natural Resource Conservation Service).

The industry has continued to grow and adopt many new and improved products to help keep soil in its place and to trap sediment before it leaves the site. Unfortunately, some of these products can be hazardous to some wildlife.

My first experience with rolled erosion control products (RECPs) was a project in Maine around 1997. I received a phone call from the Maine Department of Environmental Protect stating that the site looked good except that there were several songbirds stuck in the erosion control blanket. We were asked to visit the site and remove all the RECPs. The impact of RECPs on wildlife has been recognized and written about for years.1, 2, 3, 4

Regulations

Both federal and state agencies focus on wildlife-friendly stormwater regulations. The U.S. Fish and Wildlife Service provides recommendations and specific rules are being adopted by states across the country from California to Indiana and Minnesota to Vermont.5 Many of these focus on types of RECPs that are allowed to be used. In New Hampshire, mostly due to a recent court case,6 the New Hampshire Fish and Game Department is providing input to New Hampshire Department of Environmental Services on wildlife-friendly materials to use in stormwater design. In Massachusetts, where endangered turtles were found in the vicinity of an airport project, not only were the turtles radio tracked during the construction, but the silt fence and construction entrances were modified to prevent turtles getting in, and if they did, providing a means for them to escape. Turtles traveling to and along the silt fence encountered a ramp that took them outside the construction site (Figure 1). In both of these states, a major component of the permitting and construction is to train the contractor on how to identify the species of concern and what to do if the animal is found (Figure 2).

Figure 1. Modification of silt fence to provide exit ramps that allow turtles that find their way into a construction site to escape.

Rolled Erosion Control Products

Rolled erosion control products are made from a variety of materials and typically have a matrix fiber for erosion protection and a netting to hold the product together. The RECP selection is based on the product’s performance criteria, which includes percent effectiveness, cover factor, vegetation establishment, functional longevity, and project requirements such as slope gradient and site condition. The matrix is typically composed of straw, coir or wood fiber with a netting made of a biodegradable or plastic netting. Since at least the early 2000s, the industry has recognized the negative publicity of animal entrapments in erosion control blankets and has made adjustments to lessen the impact of the product.

RECP netting is divided into two main categories — plastic netting (Figure 3) and biodegradable fiber netting (Figure 4) — with at least one manufacturer offering a net-free option. The plastic netting is welded with varying opening sizes, often in the range of one-half inch (1.2 cm). It is designed to either be a permanent net or a mesh that is considered degradable, usually though the process of photodegradation. The biodegradable netting is woven from natural products, usually jute or coir. Because the biodegradable netting is woven, the openings are able to move and enlarge as they are pulled.

The matrix material used has been selected based on the slope length and steepness, the length of time it is needed to protect the soil surface and the expected velocity over the surface. The netting choice has often been a consideration of the use after the vegetation has grown. Biodegradable netting can take as long as two years to degrade and can cause issues if the intent is to have a mowed lawn area, where the plastic netting is often photodegradable and can break down within four months.

Newer products on the market have evolved to address the concerns of animal entrapment. The U.S. Fish and Wildlife Service recommends a minimum opening size of 1 inch (2.54 cm). Manufacturers have adjusted their plastic netting to increase the opening or elongate it. Some have used more flexible plastics to allow for some give. Other manufacturers have changed the biodegradable netting to allow it to break down quicker or have developed RECPs that have no netting by incorporating longer fibers that tie together better.

One concern with the limits on the use of RECPs are the turf reinforcement mat (TRM) products. These RECPs are designed to increase the shear strength of the vegetation to allow for the replacement of riprap or other hard armoring, allowing swales and discharges to streams and other water bodies to provide treatment and lessen thermal pollution. A major component of these mats is permanent plastic meshes. These TRMs provide water quality benefits for swale discharging directly to waterbodies and can often reduce the thermal pollution cause by alternative rock lined swales. This suggests that there is still a need for some RECPs with a plastic component or a need to find workable alternatives.

Figure 3. Straw and coconut matrix with permanent plastic mesh.

Hydraulically Applied Mulches

An alternative to RECPs may be hydraulic mulches (HMs) and hydraulic erosion control products (HECPs), which are also manufactured from a variety of materials. These HMs and HECPs, conform to similar performance criteria as RECPs: percent effectiveness, cover factor, vegetation establishment, ecotoxicity and functional longevity to align with the project requirements, slope gradient and site condition. Because the concerns with netting and plastics are not a concern with HMs and HECPs, they are a good alternative to RECPs but have tradeoffs as well. The HMs and HECPs are designed specifically for temporary erosion and sediment control and can be specified and installed on slopes up to 1H:1V. However, they are not recommended for channels or areas with concentrated water flow unless used in conjunction with RECPs designed to accommodate the anticipated hydraulic conditions.7 Like RECPs, and for that matter any erosion or sediment control measure, HMs and HECPs need to be specified based on site conditions.

All HMs, HECPs and RECPs require slope interruption devices, typically a wattle or log that will spread the flow down the slope before it concentrates. Hydraulic mulches can include amendments along with seed and fertilizers that correct or improve imbalances within the soil.

Figure 4. Coir netting with biodegradable netting in place.

Silt Fence and Alternatives

Although, the removal of erosion control measures should be a part of an erosion control plan, they are often left as an afterthought and sometimes, left behind. Silt fence left in place for too long tends to break down and lose its integrity. The result is a very loose open weave that has been known to trap animals. The alternatives include compost socks and straw wattles. Although wattle netting tends to be smaller and has not raised concerns, there is a potential for issues in some jurisdictions and with some endangered species. The compost sock alternative has a finer mess and may be less of a concern, but it may also be denser and not allow for the proper balance of velocity control and spreading of concentrated flow. As an aside, it has been observed that in some areas, straw wattles are an attractive nuisance as the netting has been chewed through and it appears small rodents have attempted to take up residence in the wattles.

What is old is new again. On sensitive sites it may be possible to use alternative materials that have somewhat fallen out of favor. On most construction sites in the Northeast, contractors are either using a hydraulic mulch or an RECP. The use of hay, mulch or straw if weed seeds are a concern could be a good alternate option. Applying a tackifier or crimping the material into the ground eliminates the need for any netting. In addition, the use of natural mulches in some regions can be both a good slope break to replace compost socks and straw wattles or can be used as a mulch cover for temporary protection.

The stormwater industry has been aware of some of the negative effects of various products on wildlife. There have been good attempts to modify products to meet both the site needs and wildlife concerns.

However, as development pushes further into areas with endangered species, the industry will need to be flexible in the design and implementation of practices or will be forced through regulatory requirements, concerned citizens and the court system to find solutions. With an understanding of the wildlife needs, existing practices can be modified to balance the site construction with the wildlife. It doesn’t have to be an either-or scenario. 

References

  1. Barton C, Kinkead K. 2005. Do erosion control and snakes mesh? Journal of Soil and Water Conservation, Volume 60(2): 33A-35A.
  2. California Coastal Commission. 2012. Wildlife-friendly plastic-free netting in erosion and sediment control products. Water quality fact sheet series. Accessed 16 September 2022.
  3. Kapfer JM, Paloski RA. 2011. On the threat to snakes of mesh deployed for erosion control and wildlife exclusion. Herpetological Conservation and Biology 6:1-9.
  4. Minnesota Department of Natural Resources. 2013. Wildlife-friendly erosion control. Accessed 16 Sept 2022.
  5. Starking, Melissa. 2021. Wildlife-Friendly Erosion Control. U.S. Fish and Wildlife Service. 2021.
  6. Appeal of Fournier, 2019 WL 6040519, State of New Hampshire Supreme Court.
  7. Profile Products. 2021. Technical Comparison – Erosion Control Blankets vs. Profile Products Hydraulically-applied Erosion Control Products.

About the Expert

Randall Schuey, CPESC, CWS, CSS, is an environmental project manager and senior scientist at Northpoint Engineering LLC.

Durham County Goes Electric

Figure 1. Durham County inspectors access all project documents via mobile devices in the field.

Inspection reports, file folders, erosion control plans, applications, deeds, project checklists…

A local erosion control program can go through a lot of paper — hardly a sustainable practice. With over 200 active erosion control permits and projects, staff driving all over the county to inspect sites, a pandemic that closes offices to the public, and staff who are working remotely, you have a perfect storm — or a perfect opportunity — for a new way to do things.

Durham County, North Carolina is now utilizing three new, innovative, electronic methods to both control the amount of paper it receives and produces, and geographic information system (GIS)-based tools for managing its inspections.

COVID-19 completely altered the global workplace, and Durham County’s Erosion Control Program was not immune to the challenges it created. Construction in Durham did not slow during the pandemic and the county worked to identify and implement electronic means for plans submittals, plan review and payments to continue meeting our objectives and provide quality customer service as though nothing had changed.

The first of three key tools in solving the problem faced was the utilization of a cloud-based content management system. With Box, the program was able to not only develop and provide online portals for engineers and consultants to electronically submit plans, but it gave us the ability to house all project information in one easily accessible place. Staff can access project files at home, at work and out in the field. A cloud-based system also provides the opportunity for staff to communicate and collaborate directly with customers regarding project comments and approval.

The next tool to reduce paper consumption and assist customers remotely was the ability to provide plan review comments electronically via Bluebeam Revu®.

Previously, comments were handwritten or typed on a document and would reference a specific location on the plans where the change was requested. Bluebeam gives staff the ability to add comments and draw changes directly on the plans and if needed, staff can review and markup plans together in real time without the need to be in the same location. Similarly, staff can work through reviews with engineers in real time to come up with the best solutions for preventing potential site concerns.

Figure 2. A GIS-based database containing information on all permitted projects.

Another key tool to move plan submittal and permitting online was the implementation on an online payment system via Paymentus. Consultants and other permittees had been clamoring for an option to pay fees online or with credit cards for years. With the implementation of online payments, review fees for submittals can now be paid online, which has reduced the number of mailed or hand-delivered checks. Not only did the online payment system fulfill the development community’s request, but it also helped to limit the time administrative staff spend in the office collecting checks and handling deposits.

The final component of the program’s efforts to go electronic is the use of GIS in our inspections program. In the summer of 2019, the county began beta testing iPads outfitted with GIS survey software to conduct its inspections and fill out electronic inspection reports which are then housed in a GIS database.

While this transition was slowed by the pandemic, the database is now fully operational. The database makes use of Esri’s ArcGIS Survey123 and allows for staff to complete inspections on any mobile device with the app. Inspection staff can use tablets (Figure 1), or even their phones, to fill out inspection reports in the field and send them directly to site contacts via email before leaving the project. Photos may be attached and problem areas geo-referenced for quick identification of issues to be addressed.

Additionally, with Box, staff can access electronic plan sets for use on site. Back in the office, staff have access to a GIS-based database containing information on all permitted projects (Figure 2). Projects are represented as points with different colors representing project status. The categories include In Compliance, Not in Compliance and Notice of Violation. The record also indicates if the project has not been inspected within a month. This allows staff to prioritize sites as well as optimize their driving route to save time and fuel.

Mounds of paper, stuffed file cabinets, inspectors running all over town to different sites — these are just some of the challenges local government erosion control programs face. However, as Durham County’s Erosion Control Program has shown, there are better methods for document storage, communications with developers, and even creating driving routes for inspectors. All these practices create not only a more efficient program, but also a more sustainable one. 

About the Expert

Ryan D. Eaves, PE, CFM, CPESC, is the Stormwater and Erosion Control Division Manager for Durham County in Durham, North Carolina. Eaves holds a bachelor’s in Environmental Science from Virginia Tech and an MPA from the University of Georgia. He has over 16 years of local government stormwater and erosion control experience.

1...111213...19Page 12 of 19

MOST POPULAR

Load more