Ecological Management Action Plans

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EM-2 Freshwater and Sediment Diversions

EVALUATION METHODS

N.B. In many cases the use of Controlled Diversions is planned in conjunction with Outfall Management schemes. The Outfall Management components are similar to Hydrologic Restoration projects detailed in EM-1. Monitoring strategies for these components of the diversions should be as described under EM-1.

Specific actions cannot be determined until after completion of modeling studies and Mississippi River Sediment, Nutrient and Freshwater redistribution feasibility study.

The following criteria will be used to determine if plan implementation steps were accomplished:

Three types of projects are envisaged: Controlled Diversion (CD), Small Scale Diversions (SD) and Uncontrolled Diversions (UD). The following criteria will be used to evaluate the effectiveness of individual freshwater and/or sediment diversions in meeting Action Plan objectives. Specific criteria may vary depending upon the characteristics of individual projects.

Plan Implementation - The activities of the BTMC and provision of BTNEP deliverables on modeling, as outlined in the above criteria, will be monitored by an independent Third Party.

Project Effectiveness - Steyer and Stewart (1992) list variables which may be measured to monitor freshwater and sediment diversions implemented under CWPPRA. It is recommended that this model be followed, whether or not any particular project is funded by CWPPRA. Generally, UD projects correspond with Sediment Diversions as defined by CWPPRA with CD and SD projects corresponding with freshwater diversions. Measurable parameters identified by Steyer and Stewart (1992) have been prioritized by Steyer et al. (1995) into Essential Variables or Additional Variables or Substitutions as shown in Table EM2-xxx1. These have been assigned a priority for monitoring under the CCMP Action Plan. The priorities have been assigned based upon the broader mission of the CCMP compared to CWPPRA (restoration, creation or enhancement of vegetated wetlands is not necessarily the primary goal of CCMP Action Plans) and the objectives of the projects as described in the Action Plan. However, priorities for monitoring variables may vary based upon the characteristics, objectives and design of individual projects.

Table EM2 -xxx1. Steyer et al. (1995) classification of monitoring variables for freshwater and sediment diversions.

^a Not considered by Steyer et al. (1995)

In addition to the parameters in Table EM2-xxx1, it is recommended that the following parameters be measured to ensure that there are no adverse impacts associated with project implementation:

These measurements should be given lower priority than those in Table EM2-xxx1.

The other criteria concerning potential adverse impacts (e.g., impacts on backwater flooding) should not or cannot be measured directly but BTMC should be made aware of any complaints that are received by the implementing agency concerning these issues that directly relate to the project.

This section provides guidance on the types of data collection methods which are currently available and appropriate for monitoring these types of projects. There may be alternative existing or new techniques which could be adopted as long as they confirm to the data quality objectives described under QA/QC.

Plan Implementation - The criteria for plan implementation will be assessed by an independent Third Party who will attend relevant BTNEP modeling, BTMC and CWPPRA meetings, assess the minutes of these meetings, and provide monitoring reports to BTMC.

Habitat Mapping - The procedures and methods outlined by Handley (1992) and Steyer et al. (1995) should be followed.

Salinity - The procedures and methods outlined by Powell (1992) and Steyer et al. (1995) should be followed. At least one continuous recording salinity gauge should be installed at each project and reference site.

Water Level - The basic procedures and methods outlined by Powell (1992) and Steyer et al. (1995) should be followed with the following detailed recommendations. At least one continuous water level gauge should be installed at each project and reference site. These gauges should be sufficiently accurate to record changes in water level of 1 cm and pressure transducers should be vented to allow for automatic correction of changes due to atmospheric pressure. If unvented transducers are used, data must be corrected for changes in barometric pressure.

Vegetation - As the monitoring criterion addresses coastal marsh productivity, rather than the abundance of species or communities, the recommendations of Steyer (1992) concerning aboveground biomass and of Steyer et al. (1995) concerning biomass measurements should be followed.

Fisheries - Sampling of oyster leases is addressed by Minello (1992) and a variety of techniques are discussed. In this case, the monitoring goal is to identify any adverse impacts on adjacent oyster leases and the Nestier tray and Butler plate techniques recommended by Minello (1992) should be used to examine survival of existing oysters and settlement of oyster spat on appropriate leases. If long-term data sets already exist for the project area using other gear, these techniques should be considered in the development of individual monitoring plans.

Discharge (Velocity and Cross-sectional Area) - Powell (1992) and Steyer et al. (1995) describe general methods for the measurement of discharge. These methods should be followed. Direct measurement of discharge requires data for velocity and cross-sectional area. It is recommended that rating curves be developed for the discharge points of diversions sites such that detailed information on velocities and areas can be used over a longer period to interpret discharge from measurements of stage.

Precipitation - Continuously-recording, tipping-bucket rain gauges, as described by Powell (1992) and Steyer et al. (1995) should be used to measure rainfall inputs to the project area. Wind shields should be used on all rain gauges.

Wind Speed/Direction - Automatic wind speed and direction equipment should be used to measure this parameter, as described by Powell (1992) and Steyer et al. (1995). Sensors should be placed at a standard height above the ground (e.g., 2 m or 10 m) in order that data can be compared to data collected by the Louisiana Office of State Climatology for various sites in BTES.

Bathymetry/Topography - Bathymetry and topography should be measured using the techniques outlined by Steyer and Stewart (1992) and Steyer et al. (1995) noting that recording fathometers, measuring in m, should be used for bathymetric and topographic surveying with either GPS or conventional rod-and-level techniques recommended. The choice of survey techniques should be determined by the acceptable level of error and the sophistication of the available technology and equipment.

Total Suspended Solids - Various methods for measurement of total suspended solids concentration are described by Powell (1992) and Steyer et al. (1995). The difficulty with point measurements is their inability to resolve vertical and horizontal variations in the total suspended solids field, as well as temporal variations in total suspended solids concentration. Methods developed by Meade and Stevens (1990) for the measurement of total suspended solids discharge account for these variations but are sample-intensive. A combination of approaches should be adopted for UD projects where the main objective is to divert sediments. The equal-width-increment, depth-integration method (Meade and Stevens, 1990) should be used in conjunction with deployment of sensors which continuously monitor total suspended solids concentration (e.g., Downing and Beach, 1989). Deployed sensors must be regularly serviced to prevent fouling (as described by Powell (1992) and Steyer et al. (1995)).

Water Quality-Nutrients - The sample collection and analytical methods described by Demas (1992) and Steyer et al. (1995) should be adopted for data collection concerning nutrient levels.

Sediment Quality-Trace Metals and Synthetic Organic Compounds - Rabalais et al. (1995) note that measuring accumulation of contaminants in sediments in a receiving area provides a better indication of the potential for accumulation in organisms than contaminant measures in water samples. They also note the lack of a tight relationship between contaminant levels in sediments and those in organisms, as well as the difficulty of interpreting data concerning contaminant levels in organisms (see also USEPA, 1992). Therefore, it is recommended that this monitoring strategy address contaminants in sediments as a general indicator of the impact of diversions on contaminant levels in the receiving area. Equipment and procedures for measuring trace metals and synthetic organic compounds should follow those of USEPA (1992).

Plan Implementation - There are no relevant sampling design or statistical analyses for the evaluation of plan implementation.

Project Effectiveness - The sampling design for monitoring project effectiveness must include comparison of the project area with an appropriate reference area. Monitoring projects without the use of a reference area can lead to misinterpretation of monitoring data through the lack of a comparative site to identify natural interannual changes in marsh processes, and/or other difficulties (Steyer et al., 1995). It is necessary to ensure that reference and project areas are comparable. Both project and reference areas should be divided into marsh habitats and replicate samples randomly selected within each habitat type. Comparison between project and reference areas should then be based at the sub-area or habitat scale (e.g., brackish marsh sub-area in project is compared to brackish marsh sub-area in reference area). If it is impossible to select a suitable reference area, as may be the case with large UD projects, then either pre-project monitoring or baseline monitoring (Steyer et al. 1995) may be adopted as an alternative. Both of these approaches reduce the validity of the monitoring results as the monitoring then fails to account for natural interannual variability in marsh processes. However, in the case of UD projects increases in wetland area are one of the main measures of project effectiveness and these are unlikely to be found under non-project conditions in BTES.

The size of the project area, the number of habitats included in the area, and heterogeneity of those habitats determine the number of samples which need to be taken and the validity of the statistical analyses. Steyer et al. (1995) describe appropriate procedures for the determination of sample size within the project area. The use of parametric (e.g., ANOVA, Student’s t-test) or non-parametric (e.g., Mann-Whitney U-test, Kolmogorov-Smirnov test) statistical procedures will depend upon the character of the datasets. If data are not normally distributed, as may frequently be the case with the collected data (e.g., salinity in a fresh or intermediate marsh), then transformations, such as logarithmic and square root transformations, should be applied and the transformed data tested for normality. If a normal distribution cannot be achieved in this manner, non-parametric tests should be used. The most basic statistical design for project evaluation is a two-tail test of whether the mean value for a measurable parameter within the project areas is equal to the mean for the reference area. If inequality is identified, further analyses can then determine if the effect of the project is to increase the parameter or decrease the parameter. In the case of UD projects comparisons may be more appropriate between one time interval and the next in order to identify progressive changes in wetland area. Standard linear regression models can be used to detect trends once sufficient annual data points have been obtained (fifteen years is considered the minimum for such trend analysis by Rabalais et al., 1995). Models having probability values of > 0.05 should be rejected, allowing determination of a trend significantly different from zero (i.e., change through time as opposed to no change through time).

Plan Implementation - The cost estimate is based upon attendance at approximately 4 meetings per year and appropriate reporting. The level of effort is estimated at 56 person-hours and costs including salary, fringe benefits, overhead and associated expenses are approximately $2,800.

Project Effectiveness - Estimated costs for evaluating freshwater and sediment diversion projects have been developed for CWPPRA by Steyer and Stewart (1992). The actual costs depends upon the size of the project and the number of stations sampled/samples collected. These estimates have been revised where possible in consideration of the recommendations presented here regarding measurable parameters and data collection methods. Ranges are presented for cost estimates on an annual or per sample basis (Steyer and Stewart, 1992) in Table EM2-xxx2.

Table EM2-xxx2. Cost estimates for monitoring freshwater and sediment diversion projects (after Steyer and Stewart, 1992).

The cost estimated for monitoring nutrients is $50 per sample.

For freshwater diversions (CD and SD) implemented by CWPPRA, average annual monitoring costs shall not exceed $25,875. This amount is reduced to $8,625 for sediment diversions (UD). The amounts for freshwater diversions are further pro-rated according to project size (Steyer et al. 1995) as follows: less than 1000 acres - 60%; 1000-5000 acres - 70%; 5000-15,000 acres - 80%; and greater than 15,000 acres - 100%. These requirements may constrain the development of monitoring plans for CWPPRA projects to below ideal levels which are more realistically reflected in the cost estimates of Steyer and Stewart (1992).

Monitoring of plan implementation will be undertaken by an independent Third Party who will prepare semi-annual reports describing actions of the BTMC and CWPPRA in relation to freshwater and sediment diversion projects. Evaluation of monitoring reports concerning project effectiveness will be conducted by qualified individuals representing organizations independent of any agencies or institutions funding the project construction, operation and/or maintenance. Semi-annual reports will be prepared. The monitoring reports will be submitted not less than 15 days prior to a regularly scheduled meeting of the BTMC and the parties responsible for monitoring will appear at the meeting to discuss the report. Monitoring reports concerning project effectiveness will also be provided to the agencies or institutions funding project construction, operation, and/or maintenance, as well as landowners for the project and reference areas (as appropriate).

The Quality Assurance Plan involves the following components:

The Quality Assurance Plan involves the following components:

Project Description - (as provided in Action Plan).

Project Organization and Responsibility - (to be prepared by monitor in association with lead implementor).

Data Quality Objectives - For the measurable parameters recommended in this monitoring strategy, Table EM2-xxx3 presents these objectives as determined by Steyer et al. (1995). Data quality objectives for sediment trace metals and synthetic organic compounds will vary between the individual substances identified in the analyses.

Table EM2-xxx3. Data Quality Objectives for identified measurable parameters (all from Steyer et al., 1995).

Sampling Procedures - The data collection methods are as described above. The sampling design will be determined for each individual project by a committee composed of BTMC representatives, the lead implementor of the project, and the monitor.

Sample Custody - Collected samples will be in the custody of the monitor from collection to sample processing. Should contractors be utilized for sample processing, written documentation of sample transmission and receipt shall be maintained by the monitor.

Calibration Procedures - Routine calibration of field and laboratory equipment will be undertaken in accordance with manufacturer’s instructions or at least annually. Written documentation of the calibration procedures and records shall be maintained by the monitor.

Analytical Procedures - The procedures described by Steyer et al. (1995) and references therein will be followed for analysis of the identified measurable parameters.

Data Review, Validation and Verification - The general procedures described by Steyer et al. (1995) and references therein will be followed. Data will be entered into a DIMS compatible database and statistical analysis will follow procedures agreed to by the BTMC, lead implementor and the monitor.

Problem Identification - Any significant problems identified during the monitoring period, either with monitoring procedures or project effectiveness, will be reported to the BTMC and lead implementor before the next regularly scheduled report is due.

Reporting - Semi-annual reports will be prepared. The monitoring reports will be submitted not less than 15 days prior to a regularly scheduled meeting of the BTMC and the parties responsible for monitoring will appear at the meeting to discuss the report. Monitoring reports will also be provided to the agencies or institutions funding project construction, operation, and/or maintenance, as well as landowners for the project and reference areas.

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