Attachment_L_-_Method_of_Approach SWCA.pdf

TMDL and Watershed Modeling and Application: Attachment L

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ATTACHMENT L: METHOD OF APPROACH

1.0 IDENTIFING POTENTIAL POINT AND NONPOINT POLLUTANT SOURCES

SWCA Environmental Consultants (SWCA) understands that a key component of the Total Maximum Daily Load (TMDL) process is identifying the source of pollutants and assessing the relationship between each source and water quality targets. Identifying linkages between source contributions and impairments will inform the TMDL and allow prioritization of management measures and project implementation in the target watershed(s). SWCA’s approach to identifying potential pollutant sources begins with a comprehensive watershed characterization and data review. The scope of pollutant source identifications will be informed by the cause of the impairment and size, ownership, and location of the contributing watershed(s).

Regulated point sources will be identified through a comprehensive search of existing Arizona Pollutant Discharge Elimination System (AZPDES) permits including both individual permits and a summary of activities covered under general permits within the target watershed(s) (e.g., Municipal Separate Storm Sewer System permit, Construction General Permit, and Multi-Sector General Permit). SWCA will also identify unpermitted point sources by surveying waterbodies for evidence of unregulated pipe outfalls and collection of additional water quality samples, if appropriate.

Nonpermitted point-source discharges associated with septic systems can also be assessed using the optical brightener method to determine if an outfall is connected to a septic system. For example, for a past project, SWCA worked with PacifiCorp HydroEast to document unpermitted outfalls into Cutler Reservoir as part of the TMDL development for that waterbody.

Nonpoint sources will be evaluated using a variety of data sources and spatial analyses, driven by SWCA’s knowledge of common sources (e.g., agricultural, industrial, urban, natural background) of different pollutants (e.g., nutrients, pathogens, sediment, metals). SWCA will identify the relative contributions of nonpoint sources of pollutants in the target watershed(s) by land-use practices and provide the cause-and-effect relationship between sources and water quality impairments. SWCA will work with other agencies (e.g., Natural Resources Conservation Service [NRCS], U.S. Bureau of Land Management, U.S. Forest Service, local health departments, local and regional municipalities), as needed, to obtain estimates of nonpoint-source pollution associated with agricultural operations, urban stormwater management, septic permitting, or other pollutant-specific sources. Figure L-1 shows an example of how watershed layers were used to evaluate point and nonpoint sources of pollution in the Rockport Reservoir watershed in Summit County, Utah.

SWCA will also seek stakeholder input to identify pollutant sources to ensure that the analysis is comprehensive and site-specific. Source identification could occur at a kick-off stakeholder or public meeting, or through one-on-one conversations with stakeholders, depending on ADEQ’s preference.

All sources will be cataloged by location (to at least the subwatershed level), type, ownership, and pollutant load at the source. From this initial analysis, SWCA will develop recommendations for field surveys to collect supplemental source characterization information to improve source identification and pollutant load estimates.

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Figure L-1. Spatial analysis of watershed characteristics for the Rockport Reservoir TMDL.

In addition to identifying current pollution sources, SWCA will identify probable future sources of pollution based on changes in population, land use, and development in the target watershed(s) that may result in changes to pollutant loading or processing mechanisms. We will work directly with municipalities, counties, and water reclamation districts to project changes in wastewater loading. Short-term changes (such as expanded development) and long-term changes (such as conversion of agricultural land to residential or recreational use) will be assessed together with accompanying changes in water use and pollutant runoff. These changes will be modeled using planning maps such as future land use for the target watershed(s). SWCA will characterize, to the extent possible, the type and seasonality of loading. To reduce the need for future TMDL revisions, estimated future pollution loads will be incorporated into TMDLs for creating reserve wasteload capacity. SWCA will also identify priority catchment areas and critical conditions and evaluate seasonal influences on the waterbody impairment(s). For each priority catchment area, SWCA will perform a load analysis, produce flow duration and load duration curves, and assess inputs from point and nonpoint sources.

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2.0 DETERMINING NATURAL BACKGROUND LOADING

SWCA understands that natural background loads are an important component to TMDL analysis and must be properly accounted for to ensure that the TMDL and resulting implementation plans are successful. Natural background load analysis is also an important aspect of achieving partnership with some stakeholders that question the relative contribution of anthropogenic sources. Figure L-2 shows a summary of a load analysis prepared by SWCA for the East Canyon Reservoir TMDL that included a substantial contribution from natural background sources.

Figure L-2. Phosphorus load analysis for the East Canyon Reservoir TMDL, Summit County, Utah.

Natural background loads will be estimated for each season or hydrologic scenario evaluated for the TMDL. SWCA’s approach to determining natural background loading will depend on the impairment and watershed characteristics, and include using one of the following general approaches:

1. Using watershed model simulations that assume a natural landscape and land use. For example, nutrients and sediment can be estimated using the Soil and Water Assessment Tool (SWAT) model and setting all hydrologic response units (HRUs) to a natural forested, desert, or grassland land use class.

2. Isolating the natural sources of a pollutant or contaminant in the analysis. For example, natural background sources of Escherichia coli can be estimated for wildlife sources using the Bacteria Source Load Calculator or Pollutant Load Estimation Tool.

3. Using empirical analysis of a similar waterbody and watershed that remains in a more natural state. For example, natural background sources of metals can be estimated using empirical water quality data from a watershed with geology and topography similar to the watershed with an impaired water.

4. In lake and reservoir TMDLs, calculating the contribution to annual loading from internal sediment cycling using reservoir models and mass-balance calculations. Although internal loading from sediments is often related to historic pollutant loads, this source must be treated separately from current pollutant sources.

Figure L-3 shows seasonal influence of the net releases of phosphorus into East Canyon Reservoir. Positive values represent internal load sources and negative values indicate that the reservoir is acting as a sink. The

Page | 4 mass balance was used to estimate internal load as 24% of the total annual load to the reservoir. The CE- QUAL-W2 model was used to calculate a 10-year timeframe to flush legacy phosphorus loads from the reservoir and reset the natural background regime.

Figure L-3. Monthly phosphorus mass balance for East Canyon Reservoir for water years 2003-2007.

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3.0 DEVELOPING TMDLS AND/OR WATERSHED MODELS

Development of TMDLs requires analysis and modeling of watershed sources and receiving water responses. In this section, we have outlined our approach to model development. The application of models for use in TMDL development is further described in sections 4.0 and 5.0.

DEVELOPING A CONCEPTUAL MODEL

SWCA will develop conceptual system models, as necessary, for TMDL studies. Conceptual models will be informed by existing data, as available and agreed upon by ADEQ and SWCA. Facilitating meetings with agencies and other stakeholders is often an excellent first step in creating the conceptual model by formalizing the concepts of watershed, stream, and receiving water processes . Conceptual models help to clarify relationships between the physical setting of the watershed, land uses and management, pollutant sources, and water quality targets. The ultimate goal of such models is to identify the key pathways that lead to exceedances of water quality criteria and the processes that can be managed to attain water quality targets. Once the nature, extent, and causes of impairment have been identified, appropriate TMDL modeling approaches, source assessment and load allocation methods, and best management practices (BMPs) for implementation can be selected. SWCA has experience creating stressor response diagrams, linkage diagrams to describe an impaired system (Figure L-4), scenario matrixes, stream flow diagrams, and associated maps.

Figure L-4. Linkage diagram of factors influencing low dissolved oxygen in Cutler Reservoir, Utah (solid and dotted lines indicate increasing and decreasing relationships, respectively).

CANDIDATE MODEL REVIEW

Selection of an appropriate TMDL watershed and/or receiving water model and methodology is a critical step in developing technically sound TMDLs that quantify loads and lead to effective implementation of BMPs for priority sources and critical areas. Model selection should be determined based on the goals of the participants, availability of data, project deadlines, and funding limitations, rather than being determined by scientists’ preferred modeling platform and methodology. Models can also be predictive or used to compare proposed management plans and explore their effects on other processes. Modeling tools can be especially useful in communicating complex processes, spatial patterns, and data in a visual format that is clear and compelling. When appropriately applied and

Page | 6 applicable assumptions are utilized, these modeling tools can empower stakeholders to move forward with concerted efforts to address an ecological problem.

SWCA has experience using a wide range of modeling tools to develop TMDLs ranging from empirical and statistical models to spatial models and mechanistic models. SWCA believes that it is important to maintain ‘model neutrality;’

that is, to survey the available tools and select tools most appropriate to answer the questions required by a project, rather than to turn to models and modeling platforms that are most familiar. SWCA aims to select the simplest model to answer the questions posed by a project with an acceptable amount of uncertainty. We consider the following criteria in evaluating candidate models for use in TMDL analyses:

• Data quantity and distribution

• Degree of hydrologic alteration and management in the basin

• Pollutants of concern

• Likely pollutant sources

• Utility of the resulting implementation plan

• Adaptability (to recalibrate as additional data are obtained)

• Simplicity, transparency, and transferability

• Cost and schedule

Selection of an inappropriate TMDL methodology could result in a higher than necessary degree of uncertainty and/or misidentification of sources, priority areas, or contributing factors to the impairment. Likewise, the methodology must be well paired with implementation planning to make the TMDL results useful to watershed planners.

SWCA aims to select models that are as transparent and flexible as possible, given the needs of the project. We feel strongly that model complexity must be dictated by the questions posed by the project, as well as available data and information. Models that are too simple are less precise and explanatory; however, a model that is too complex can lose transparency and accuracy. We have found that in many cases, a simple model that can be well communicated and explained is more useful than a complex model that has narrow applicability, high costs of data inputs, and compounded uncertainty.

We have found that in some cases, tools as simple as Microsoft Excel can be the right choice. One major benefit of Microsoft Excel is that it is readily available and, in most cases, many stakeholders are already familiar with it. We generally select simulation (process) models to help determine the mechanisms and underlying driving forces of patterns that cannot otherwise be described statistically using existing data. We rely on geographic information systems (GIS) to model the spatial connectivity and landscape patterns present in a watershed.

DATA USE

SWCA has experience using many types of data in model development, simulations, and calibration/validation. Some data are used to drive mechanistic models, including climatic data, spatial data (soil and land-use characteristics), and upstream flow and water quality data. Flow and water quality data are generally used to calibrate and validate models.

Spatially explicit source identification data are used to estimate loads from nonpoint sources. SWCA will provide all raw, intermediary, processed, and output data to ADEQ in tabular format.

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4.0 DEVELOPING PREDICTIVE MODEL SIMULATIONS

TMDL CALCULATIONS

Selected models will be used first to simulate current pollutant loads in impaired receiving waters, as well as the relative contribution to the current load that is derived from each point and nonpoint source in the watershed. The TMDL for the impaired water will be established using the hydrologic model output and identified water quality criteria.

The averaging period for the TMDL may be seasonal, monthly, or annual, in addition to reporting total daily loads.

The SWCA team will identify pollutant loading in watersheds from permitted and unpermitted point sources and critical source areas where nonpoint sources have high potential to introduce significant pollutant loading to vulnerable or impaired waters. One example of identifying critical source areas is using spatial layers of slope, land use, and proximity to a stream to develop critical area rankings for agricultural fields near an impaired stream reach.

The SWCA team’s water resources scientists will work with SWCA’s GIS specialists to compile relevant spatial data sets that characterize the target watershed(s). SWCA will create maps to integrate and visualize water quality data analysis results, land use (and land use coefficients) data, stormwater data (National Stormwater Quality Database), permitted point sources of pollution, land ownership, and other relevant spatial data to identify specific areas of concern and sources of point and nonpoint source pollution.

Once the TMDL has been established, the margin of safety (MOS) will be selected or calculated and subtracted from the total load allocation to the impaired water. The MOS is a required component of TMDLs that accounts for uncertainty in the TMDL analysis. The U.S. Environmental Protection Agency (EPA) allows the MOS to be expressed either implicitly through the use of conservative assumptions, or explicitly as unallocated assimilative capacity of the waterbody. SWCA typically follows Dilks and Freedman’s approach to selecting an appropriate MOS, which considers the following criteria in MOS selection:

• Uncertainty in TMDL calculations

• Desired degree of protection and assurance of TMDL attainment

• Data limitations that lead to high uncertainty, a high MOS, and therefore a small allowable load

• Feasibility of implementation

Following selection and calculation of a MOS, the remaining load is the load that will be available for allocation to the source(s) in the target watershed(s). It will be compared to the current load and allocated among point and nonpoint sources in the form of wasteload allocations and load allocations, respectively. Load allocations are most commonly calculated based on the portion of the current load that each source is responsible for. However, EPA has identified 19 different mechanisms by which loads can be allocated in a TMDL. SWCA has experience implementing many of these allocation methods in consultation with agency representatives and local stakeholders.

SCENARIO EVALUATIONS

SWCA will develop scenarios in partnership with ADEQ and other stakeholders. Scenarios could include simulation of water quality under various climatic scenarios (e.g., wet versus dry seasons or years) to evaluate 1) alternative water quality endpoints (site-specific criteria); 2) alternative implementation measures, and 3) alternative loading scenarios for receiving waters. Scenarios can also be run to represent different combinations of watershed load reductions to maximize pollutant load reduction while minimizing costs. Once scenario model runs have been completed, a summary of scenarios will be presented in graphical and tabular format for evaluation by ADEQ decision makers.

As an example of SWCA’s experience with scenario modeling, we have included results from scenario runs of the BATHTUB reservoir model for a reservoir in northern Utah. The BATHTUB model was used to identify site-specific water quality criteria for total phosphorus in different portions of the reservoir (Figure L-5).

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Figure L-5. Scenario modeling of alternative total phosphorus endpoints for Cutler Reservoir, Utah.

MODEL DEVELOPMENT REPORT AND TRANSFER TO ADEQ

SWCA will synthesize all data used in the model, model files, output files, and summary graphics into a clear and concise model report that will follow the outline identified in the Task Order Scope of Work (TOSOW). SWCA will provide all model files, data, output, and the model report, as well as a ‘cheat sheet’ for the model with hyperlinks to specific model files and folders (such as input files, output files, model handbook, etc.), to ADEQ as described in the TOSOW. S SWCA will also provide ADEQ staff with technical assistance regarding the model’s framework, model operation (including modifying input files), development of alternative scenarios, and source and output data, per the

TOSOW.

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5.0 CALIBRATING AND VALIDATING THE CONCEPTUAL MODEL

The method used for calibration and validation of models depends on the type of model, intended use of the model for explanation or prediction, risk associated with model error, and resources available for model improvement.

Generally, 80% of a dataset will be used for model calibration and 20% will be set aside for model validation.

Examples of our model calibration experience below include a table showing calibration outputs from the SWAT watershed model for hydrology (Figure L-6), a calibration graphic dissolved oxygen in Cutler Reservoir from the BATHTUB model (Figure L-7), and a validation graphic (post-calibration) for metalimnetic oxygen depletion rates in Echo and Rockport Reservoirs (Figure L-8).

Figure L-6. Hydrologic calibration results for the SWAT model used in the Rockport and Echo Reservoirs TMDLs.

Figure L-7. Summary of Total Phosphorus calibration for Cutler Reservoir (BATHTUB model).

Figure L-8. Model validation of metalimnetic oxygen depletion rates in the dam segment (deepest) of each reservoir. MOD is critical to predicting late season dissolved oxygen in the hypolimnion driven by decay of spring and summer algal blooms.

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In watershed modeling, the situation often arises where data are only available for one watershed in the region. A model can be calibrated and ‘validated’ for this watershed, and then extrapolated and used to model processes in other nearby watersheds. In such cases, SWCA will work with ADEQ to collect sufficient site-specific data to ensure that the model is a reasonable approximation of the dynamics and water quality in the target impaired waterbody.

Additionally, all assumptions associated with any watershed modeling will be clearly outlined and shared with ADEQ for approval prior to implementation.

Sensitivity analyses assume that the relationships in the system and the model are similar (i.e., the model has been verified), such that the model can be used to identify which parameters lead to the greatest change in system behavior. These parameters can be the targets for implementation and monitoring. Sensitivity analyses will be used to quantify uncertainty in the TMDLs and can be incorporated into a calculated MOS during the load allocation portion of the study.

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6.0 IDENTIFYING AND ADDRESSING DATA GAPS

SWCA understands the importance of identifying data gaps early in the TMDL development process or in any watershed modeling effort. SWCA summarize existing information in four categories: documents, spatial layers, time-series data (flow/water quality), and static data (water use statistics). In many cases, source identification data are not available for use in a TMDL. SWCA will work with agencies and other stakeholders to gather source identification data that may not be publicly available. For example, SWCA has successfully obtained animal unit data from the NRCS for past projects. These data were aggregated at a watershed and subwatershed scale to provide source estimates from livestock, even though the data are not publicly available. When necessary, we will gather hardcopy maps, reports, and other records from local planning offices (e.g., septic permits), other state agencies (e.g., wildlife herd data or fishery reports), and water managers (e.g., irrigation district managers) to provide ranges of water diversions during the irrigation season—an important distinction from water rights data.

SWCA will compile and review existing data sources and incorporate any other relevant, publicly available, planning documents and data sets as needed, including, but not limited to, ground water data, hazard mitigation plans, community wildfire protection plans, and drought mitigation plans and data. As much as possible, our team will integrate existing data collection efforts and data to ensure that we build on the wealth of knowledge already available.

Following the initial stages of data compilation, SWCA will use a compiled database to identify data gaps (i.e., gap analysis). Gaps could include a lack of paired flow and concentration data deemed useful for calculating pollutant loading or detailed land use data that has never been collected but would be beneficial for understanding pollutant sources. Critical gaps will either be remedied with appropriate contacts, by work conducted in a monitoring effort, or if unable to be filled, discussed with ADEQ along with potential recommendations and strategies for remediation.

Table L-1 shows example monitoring objectives and potential data types to address each objective that SWCA has identified in previous monitoring efforts. SWCA will work with the ADEQ to determine specific monitoring objectives that will shape the development of each project-specific sampling and analysis plan (SAP).

Table L-1. Example Monitoring Objectives and Types of Data.

MONITORING OBJECTIVE TYPE OF INFORMATION COLLECTED

Gather baseline data where none exists Information survey

Field observations and photographs

Water quality grab samples, field observations, photographs, Microbial Source Tracking

Stormwater sampling

Conduct research Streamflow measurements and water quality grab samples

Water quality grab samples; physical measurements, lake sediment samples, biological samples

Identify pollutant sources Field observations and photographs

Evaluate effectiveness of watershed BMPs Multiple indicator monitoring; photographs, field observations, water quality grab samples, streamflow measurements, soil samples, biological monitoring

Assess beneficial use attainment Water quality grab samples, streamflow measurements

Evaluate long-term trends Water quality grab samples, streamflow measurements, photographs, field observations

Pollutant load model validation and calibration Water quality grab samples, streamflow measurements

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7.0 MONITORING AND DATA COLLECTION

SAMPLING AND ANALYSIS PLAN

SWCA has developed SAPs for a variety of environmental data collection efforts across the United States and has project-ready templates for sampling. SWCA will develop draft project-specific SAPs that will document the procedural and analytical requirements for any necessary monitoring and will provide the framework to oversee data collection efforts to ensure data collected is of sufficient quantity and quality to meet study goals and objectives. The SAP will outline sampling methodology, sampling schedule, sampling locations, analytical parameters for analysis, a project-specific quality assurance project plan, and other project-specific details.

QUALITY ASSURANCE AND QUALITY CONTROL

Quality assurance and quality control (QA/QC) is an integral part of all SWCA’s work and is best described as a set of activities and procedures designed to assure the reliability and accuracy of data and the attainment of quality standards. QA/QC for water quality sampling efforts is addressed by establishing both field and laboratory checks that result in qualitative and quantitative measurements of data quality. Table L-2 provides a summary of example data quality indicators, the applicable QA/QC component, how it will be evaluated, the performance criteria, and example project goals. Specific project goals for QA/QC will be established through coordination with ADEQ.

Table L-2. Data Quality Indicators for Environmental Sample Collection.

DATA QUALITY INDICATOR QA/QC COMPONENT EVAULATION CRITERIA GOAL

Precision: Measure of agreement among repeated measurements of the same property under identical, or substantially similar, conditions; random error.

Laboratory duplicates Relative percent difference (RPD), laboratory reported

For concentrations > method reporting limit (MRL), RPD < 20%.

Field replicates RPD, calculated For concentrations > MRL, RPD < 20%.

Accuracy: Degree to which the result of a measurement conforms to the correct value or standard.

Equipment blanks and field blanks Method detection limit (MDL) < MDL

Standard operating procedures (SOPs) for data collection

Documentation of adherence to SOPs, including SOP acknowledgment forms and training

100% compliance

Temperature blank Sample temperature Temperature must be above freezing and < 6 degrees Celsius

Comparability: Measure of confidence that one dataset can be compared to another and can be combined for decision-making purposes.

SOPs Documentation of adherence to SOPs, including SOP acknowledgment forms and training

100% compliance

Holding times Holding times 100% compliance Analytical methods EPA or standard method 100% compliance

Representativeness: The degree to which data accurately and precisely represent a characteristic of a population, parameter variations at a sampling point, a process condition, or an environmental condition.

SOPs Documentation of adherence to SOPs, including SOP acknowledgment forms and training

All data collected following SOPs

Equipment blank MDL < MDL

Completeness: Measure of the amount of valid data obtained compared to the amount of data expected to be obtained.

Complete sampling Percentage of valid data 100% completeness

Source: SWCA SAP template, adopted from the EPA’s 2014 SAP guidance template.

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SAMPLE COLLECTION AND COORDINATION

SWCA will develop field protocols and standard operating procedures (SOPs) to guide the field collection of data for inclusion in the SAP. The SAP will be used to guide field staff training and will guide all field sample collection efforts and protocols.

All Sample collection and coordination will be led by an experienced field manager and supported by a QA/QC lead. Additionally, as part of sample collection, Quality control samples (blanks) will be collected to trace sources of artificially introduced contamination. Quality control samples will be agreed upon by ADEQ and SWCA.

Some examples of field QA/QC samples include equipment blanks, field blanks, field replicates, and trip blanks.

Information generated by field personnel, including field measurements and photographs, will be organized and accounted for at the end of each sampling day. At each sampling site, personnel will complete a field sampling form and fill out the applicable laboratory chain of custody (COC) form (obtained from the analytical laboratory before each sampling event). If field instrumentation is necessary, personnel will fill out one equipment calibration worksheet at the beginning of each day and indicate on the sheet if the instrument was recalibrated or validated on-site. As a backup method, photographs will be taken in the field of completed field sampling forms, COC, and calibration worksheets as soon as these are completed.

DATA MANAGEMENT

Following the completion of each monitoring event, all environmental data will be added to a project database. The term ‘project database’ refers to the compiled project information that is organized in a computer folder structure containing the various file types, with Microsoft Excel and R package serving as the primary tools used for project data management. Excel workbooks can be easily shared by ADEQ with a larger planning team, project stakeholders, and potentially shared with the public. This allows for more meaningful dialogue and review of processes, calculations, and assumptions.

SWCA will summarize analytical laboratory results for all field samples analyzed—including method detection limits (MDLs), quantitation limits or practical quantitation limits [PQLs]), data qualifiers, and associated quality control results—and prepare a narrative summary of quality control measurement results. SWCA will coordinate with ADEQ regarding censoring data and reporting results above and below MDLs and other project-specific data needs. In addition to these details, SWCA will also provide ADEQ with the raw sampling data through an easy-to-navigate SharePoint site or other agreed upon data sharing portal.

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8.0 RESTORATION AND REMEDIATION

WATERSHED IMPLEMENTATION PLAN DEVELOPMENT AND EVALUATION

In collaboration with ADEQ and local stakeholders, SWCA will prepare a TMDL watershed implementation plan according to the TOSOW. This implementation plan will outline a strategy to reduce pollutant loading in order to attain water quality standards and restore the streams to full support status. As part of the implementation plan, SWCA will present, discuss, and evaluate the existing BMPs and completed pollution reduction and water quality projects in the watershed. We will draw from SWCA’s experience in other watersheds, the experience of stakeholders, and from EPA guidance on developing watershed plans.

The implementation plan is often most efficiently prepared in tandem with the source identification portion of a TMDL study. We have found that the most effective implementation plans are designed around management areas (which may cross subwatershed boundaries). These management areas represent the most relevant areas for watershed management measures and project implementation, and could include federally managed areas of the watershed, areas managed by agricultural conservation districts, and portions managed by specific municipalities. When sources are identified, SWCA will immediately follow up with ADEQ and then, as appropriate, with stakeholders regarding existing implementation measures and projects that relate to the source. This will streamline the source identification and implementation planning portions of the TMDL project and lead to a more comprehensive analysis resulting from effective stakeholder engagement.

The implementation plan, in conjunction with portions of the TMDL, will include the nine key elements identified by the EPA that are considered critical for achieving improvements in water quality. EPA requires that these elements be addressed in watershed plans funded with incremental Clean Water Act Section 319 funds. These elements will help provide reasonable assurance that the nonpoint-source load allocations identified in the nonpoint-source TMDL will be achieved. SWCA will prepare a watershed plan that includes EPA’s nine elements, listed below.

• Identify and quantify causes and sources of the impairment(s)

• Estimate load reductions needed to meet water quality standards

• Identify BMPs needed to achieve load reductions and critical areas where these management measures will be implemented

• Estimate needed technical and financial resources

• Provide information, education, and public participation components

• Include a schedule for implementing nonpoint source management measures

• Identify/describe interim measurable milestones for implementation

• Establish criteria to determine if load reductions/targets are being achieved

• Provide a monitoring component to evaluate effectiveness of the implementation over time for criteria identified above

SWCA water quality staff has successfully authored watershed implementation plans, and many grant applications for Clean Water Act Section 319 and other state and federal funds, resulting in the availability of more than $25 million for the implementation of TMDLs and related water quality improvement measures. This experience will aid in the preparation of an implementation plan that will include all the critical elements necessary to successfully compete for state, federal, and other funding.

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ECOLOGICAL RESTORATION

SWCA has a dedicated ecological restoration and engineering team that designs, permits, and builds environmental restoration projects. We have the expertise and the relationships to guide successful restoration projects from inception to completion, with a specialty in assessing, protecting, and restoring natural resources. With a strong track record of approvals, our team will help you achieve a swift issuance of permits and move your project forward. We combine water resources engineering with a deep understanding of natural systems to develop sustainable solutions that protect both sensitive resources and infrastructure, including habitat, rivers and streams, and recreational facilities. SWCA staff have experience in applying interdisciplinary approaches to watershed, wetland, and stream assessments for restoration, design, and plan implementation. We can provide a range of in-house experts accomplished in addressing hydrologic and hydraulic engineering, geomorphic, ecological, and economic issues typically involved in restoration projects.

Our philosophy and approach to ecological restoration is simple: use scientific means to identify and remove the root causes of the impairments to the system by employing nature-based practices, in order to have the greatest beneficial and sustainable impact on the entire stream/valley system and, when possible, the entire watershed. We take a holistic approach on a watershed or valley-wide scale for all of our restoration projects. For example, if we are working on a project with the goal of reducing sediment and nutrient loads into a system, we will not limit our focus to a single stretch of stream or river or utilize a single restoration technique.

SWCA’s design process has been developed through over a collective 80 years of fluvial geomorphic assessments and river and habitat restoration design project experience, and we consistently apply this process to river and habitat restoration projects nationwide. The first step in the design process is to clearly define the goals and objectives of the project based on conversations with the client and any associated stakeholder community. These goals and objectives are then developed into the initial design concepts and evaluation criteria for later use in alternatives analysis. The concept alternatives are developed to encompass a spectrum of restoration efficacy, project stability and resiliency, failure risk, and cost. The conceptual designs are then developed to some level between 10% and 30%, depending on the project. However, at a minimum, this level of design will need to inform not just the engineering plans, but also permitting and construction costs. All data collected, preliminary analysis performed, and results obtained, as well as resulting alternative conceptual designs, are then compiled into a Preliminary Basis of Design Report. Depending on the client and the project, the conceptual design alternatives are prepared in a form as simple as CADD-generated alignment linework in a GIS/Google Earth (.kmz) format or as complex as a 30% design plan set including an existing conditions plan, a proposed conditions plan and profile sheets, a grading plan, cross-section sheets, and planting and structure details.