Watershed and Pollutant Loading Studies
| Lake Restoration and Management
| Water Quality
Services | Sediment Studies
Stormwater Treatment | Nutrient Source Identification | BMP Design | Groundwater Seepage Evaluations
Environmental Research & Design, Inc. (ERD) is a specialized environmental engineering firm which performs projects exclusively in the areas of lake restoration, nutrient and hydrologic budgets, stormwater management, sediment-water column interactions, nutrient assimilation, algal productivity, and water quality issues. Overviews of general categories of work efforts conducted by ERD are given below.
Watershed and Pollutant Loading Studies
ERD has been at the forefront of watershed and pollutant loading studies for more than 20 years. During the early 1990s, ERD developed some of the initial spreadsheet-based pollutant loading models to estimate nonpoint source loadings from watersheds. ERD also has developed and maintained a database of event mean concentrations for runoff generated in a variety of land use categories throughout the State of Florida. During the late 1990s, ERD pioneered the use of a GIS-linked spreadsheet model for estimation of runoff volumes which combines land use categories with soil types to generate estimates of annual runoff volumes. This methodology is used today in virtually every watershed loading model used for TMDL development. ERD has developed pollutant loading models for watersheds ranging in size from a few acres to more than 100,000 acres in size. ERD also pioneered algorithms for incorporating impacts from stormwater management systems and conveyance systems into pollutant loading estimates for watershed areas which are also commonly used in most current models.
Restoration and Management
Over the past 20 years, ERD has been involved in more than 75 lake restoration and water quality evaluations. All but two of these projects have been performed on lake or river systems within the State of Florida which has provided ERD with a unique understanding of physical, chemical and biological processes in Florida surface water systems.
ERD believes strongly that the key to a successful lake restoration or water quality improvement project is a thorough understanding of the hydrologic and nutrient budgets for the surface water system, including consideration of inputs from internal recycling and resuspension of sediments into the overlying water column. ERD has become well recognized for an ability to perform detailed diagnostic evaluation studies in an efficient and cost-effective manner. Due to an extensive in-house collection of field monitoring equipment, ERD can rapidly and efficiently instrument virtually any inflow for collection of flow data and water quality samples.
Virtually every water quality evaluation performed by ERD involves development of recommendations or management options to either maintain or improve water quality characteristics within the evaluated waterbody. ERD has performed extensive research on virtually every type of structural management options currently in use for treatment of runoff and nutrient loadings into lakes. As a result, ERD has a unique level of expertise for selection of the most appropriate BMPs to achieve a particular water quality goal. Over the years, ERD has learned that water quality improvements can be achieved not only by structural techniques but also through non-structural and regulatory approaches which are designed to control and reduce pollutant inputs. ERD has an unmatched record of successful water quality improvement projects.
The extensive experience of ERD in lake restoration and water quality projects is clearly unmatched by any other consulting firm in the southeastern United States. In fact, very few international consulting firms can match the lake restoration experience of ERD, even considering projects performed in multiple branch offices throughout the world.
ERD maintains a complete inventory of state-of-the-art field sampling and monitoring equipment sufficient to successfully complete any water quality or monitoring research project. ERD owns more than 20 automatic samplers with integral flow meters for collection of stormwater runoff and baseflow; seepage meters for monitoring of groundwater inflow to surface waters; equipment for collection of surface water; equipment for installation of groundwater monitoring wells and collection of groundwater samples; equipment for recording rainfall, evaporation, water level and flow rate; equipment for collection of grab and core samples from lake bottom sediments; sample collection and research boats; and multiple 4-wheel drive vehicles. This extensive inventory of equipment allows ERD to complete virtually any water quality project with in-house resources.
ERD has conducted water quality and BMP-related research projects for a variety of governmental agencies, including the St. Johns River Water Management District, the Northwest Florida Water Management District, the Southwest Florida Water Management District, the South Florida Water Management District, the Florida Department of Environmental Protection, and the Florida Department of Transportation. BMP performance monitoring research conducted by ERD has included virtually every type of stormwater BMP in use in the State of Florida today, including wet detention, dry detention, dry retention, gross pollutant separators, filter systems, wetland treatment systems, alum treatment, as well as proprietary BMPs. The results of these projects have been used to refine designs for stormwater management systems, develop regulatory criteria, and develop water quality criteria.
ERD maintains an in-house research-grade water quality laboratory which is used solely for our own project efforts. In addition to research-grade equipment for water quality analyses, facilities are also provided for sediment nutrient analysis, algal bioassays, short- and long-term toxicity experiments, settling columns, scale model filtration systems with underdrains, soil/sediment grain size analysis, and facilities for jar test and coagulation experiments, including measurement of zeta potential. ERD has also designed and constructed a continuously stirred environmental chamber for incubation of sediments and slurries under differing pH levels and oxidation states.
All laboratory and field activities conducted by ERD are covered by an internal Comprehensive Quality Assurance Plan which is updated on a routine basis. The ERD laboratory is also certified by NELAC (#E1031026) as a Basic Environmental Laboratory and for Heavy Metals. Quality control is very important at ERD for both laboratory and field operations. Quality control is continuously monitored on all work efforts and is frequently reviewed by the Quality Assurance Officer and the Project Director.
Since ERD performs water quality testing only for projects related to surface water and groundwater, laboratory procedures have been developed to optimize measurements within the range of values normally found in these water sources. This means that ERD can provide consistently lower detection limits for significant parameters, such as nutrients, than can be provided by other laboratories which measure a wide range of parameters from industrial wastes to drinking water. As an example, the minimum detection limits for orthophosphorus and (SRP) and total phosphorus in the ERD laboratory are 0.001 mg/l and 0.002 mg/l, respectively. Most other laboratories list detection limits of 0.005 mg/l and 0.050 mg/l for these parameters. Since typical concentrations of orthophosphorus and (SRP) and total phosphorus in surface water systems are less than 0.005 mg/l and 0.050 mg/l, the reported data from these laboratories is presented as <0.005 mg/l and <0.050 mg/l which is essentially useless data. ERD also conducts measurements of chlorophyll-a using the extremely accurate fluorometric technique which is based on actual chlorophyll-a standards instead of the spectrophotometric method, which is difficult to perform and replicate, does not utilize standards, and is valid only in fresh water systems.
ERD has extensive experience in characterization of bottom sediments and evaluation of sediment-water column interactions in lake systems. Interactions between the sediments and the water column can be particularly significant in shallow lake systems. Previous research by ERD has shown that water column characteristics can be significantly affected by both sediment recycling and physical resuspension processes. ERD has performed numerous projects to evaluate the impacts of sediments on water quality, including projects in Lake Maggiore in St. Petersburg, FL, where in-lake isolation chambers were utilized to identify changes in water quality characteristics resulting from wave action within the lake and to determine the affect of dredging on lake water quality; in Megginnis Arm of Lake Jackson in Tallahassee, FL, where ERD performed another study utilizing isolation chambers to evaluate the impacts of sediment nutrient exchange on algal productivity; in East Lake, located in Tampa, FL, where ERD evaluated the impacts of sediment resuspension and recycling on water quality within the lake and as a component of the nutrient budget for the lake; and in the Winter Haven Chain-of-Lakes, where both in-lake isolation chambers and sediment incubation experiments were conducted to evaluate internal recycling and anticipated water quality improvements from proposed sediment dredging.
ERD is one of the pioneers in sediment inactivation projects within the U.S., with current personnel conducting sediment inactivation projects as early as 1982. ERD has conducted more than 26 sediment inactivation projects throughout Florida, with a combined total area of more than 5000 acres. ERD pioneered the concept of calculating required aluminum doses based upon available phosphorus within the sediments and has conducted extensive research into water column, ecological, and sediment impacts from alum addition. ERD has been involved, either in dose determination or actual application (or both), for virtually all applications conducted within Florida. During 1992, ERD developed a modified phosphorus speciation technique to identify available phosphorus in lake sediments which forms the basis for alum dose determination. This technique has become the standard for most applications conducted in North America today. ERD maintains multiple application vessels and barges and has capability of applying up to six tanker loads of alum (27,000 gallons) per day.
In the late 1970s, Dr. Harvey H. Harper, P.E., while a faculty member in the Department of Civil and Environmental Engineering at the University of Central Florida, began testing the effectiveness of liquid aluminum sulfate (alum) and other coagulants to remove pollutants, nutrients, heavy metals, and bacteria from stormwater runoff. This testing yielded very favorable results, and in the 1980s, alum treatment of stormwater runoff was evaluated for several stormwater retrofit projects, with the initial system constructed in 1987 at Lake Ella by the City of Tallahassee.
Prior to design, a preliminary evaluation phase was conducted which included extensive alum jar testing with stormwater runoff and chemical analysis of raw and alum treated stormwater. Once the system was operational, FDEP funded a 2-year study to evaluate the affect of alum treated stormwater runoff on lake water quality, lake sediments, and benthic activity. This study also evaluated the stability and accumulation rate of the alum floc. The extensive study on Lake Ella yielded extremely favorable results in all areas evaluated.
ERD has designed, permitted, and administered construction on more than 50 alum stormwater treatment systems, reflecting more than 90% of the existing systems world-wide. During 2008, construction was completed on the Lake County Nutrient Reduction Facility (NuRF) which has a treatment capacity of 300 cfs and is the largest system in existence. The system includes two floc storage ponds, a dedicated dredging system, floc dewatering system including centrifuge, and a floc storage area.
Nutrient Source Identification
ERD has conducted multiple studies to identify the sources of nutrient loadings in watersheds contributing to lakes, creeks, or estuaries. These studies have used tracers such as chloride, conductivity, coprostanol, and stable isotope analyses of nitrogen and oxygen to partition measured nutrients into the originating sources (such as stormwater runoff, reuse water, or fertilizer). ERD has conducted multiple studies to identify impacts from reclaimed wastewater used for irrigation.
ERD has extensive experience and capabilities in the areas of hydraulic modeling and design for stormwater treatment systems. Personnel at ERD have studied and designed every type of stormwater treatment facility currently used in the State of Florida, including retention ponds, detention ponds, detention with filtration ponds, grassed swales, exfiltration trenches, wetland systems, in-line and off-line chemical treatment systems, and primary and secondary conveyance systems. Research performed by ERD has provided the basis for many of the current stormwater regulations used in the State of Florida and has allowed ERD to develop pollutant removal efficiencies for commonly used stormwater management practices. This unique experience allows ERD to tailor stormwater management systems for removal of target pollutants. ERD provides complete engineering services from the study phase through design, permitting, bidding and construction administration.
Groundwater Seepage Evaluations
ERD has investigated and developed innovative methods for estimation of groundwater flux in surface water systems. Based upon the research performed by ERD, many lake managers in Florida now recognize that groundwater inflow into lake systems can represent a significant pollutant and hydrologic loading to the lake system that may alter selection of final water quality improvement options. To assist in quantification of influx from groundwater seepage, ERD has developed and refined a monitoring system for estimation of the quantity and quality of groundwater influx using seepage meters. Seepage meters have been used by ERD in over 35 lake restoration and diagnostic evaluation projects. Seepage meters are now commonly specified by governmental agencies when soliciting services for pollutant loading evaluation studies.