The SOW is intended to support the Greater Everglades (GE) module of the MAP. This SOW includes the objectives of the work effort, a general description of the scope citing the methodologies to be used, a detailed breakdown of the tasks to be performed and associated deliverables and timeframes, planning, coordination, data review, report preparation and submittal, equipment purchases, rental and ownership and project management.

Surface water levels and sheet flow in the Everglades are very sensitive to any differences in topography because of the region's expansive and extremely flat terrain. Therefore, hydrologic models require very accurate elevation data to simulate and predict water flow direction, depth, velocity, and hydroperiod. Water resources, ecosystem restoration, and other land management decisions will rely in part on the results of these models, so it is imperative to use the best elevation data available to achieve meaningful simulation results. Elevation data points are being collected every 400 meters in a grid pattern to meet the requirements of various hydrologic models. The vertical accuracy specification for these elevation data is ±15 centimeters (6 inches) as referenced to the North American Vertical Datum of 1988 (NAVD88).

Because traditional methods for collecting elevation data for the Everglades are impractical or too costly, the U.S. Geological Survey (USGS) conducted a feasibility study to determine if state-of-the-art techniques using the Global Positioning System (GPS) could meet the strict vertical accuracy specifications of the elevation data. The feasibility study successfully demonstrated that differential GPS techniques, using airboats to navigate transects, could in fact meet the vertical accuracy requirement. Also, the land surface being surveyed in the Everglades is typically under water and obscured by vegetation. This precludes the use of other methods for collecting very accurate elevation data, such as photogrammetry, Light Detection And Ranging (Lidar), Interferometric Synthetic Aperture Radar (IFSAR), or other alternative remote sensing technologies. Therefore, topographic surveys over such a large area of the Everglades with such a stringent accuracy specification can only be accomplished efficiently by using GPS technology. This is especially the case in a harsh and inaccessible wilderness environment with unique landscape characteristics such as the Everglades.

Because the Everglades is so expansive and remote and includes environmentally sensitive areas, impenetrable vegetation, or other areas unapproachable by airboat, access to many places is possible only by helicopter. To solve this accessibility problem, the USGS developed a helicopter-based instrument, known as the Airborne Height Finder (AHF), which is able to measure the terrain surface elevation in a noninvasive, nondestructive manner. Using an airborne GPS platform and a high-tech version of the surveyor's plumb bob, the AHF system distinguishes itself from remote sensing technologies in its ability to physically penetrate vegetation and murky water, providing reliable measurement of the underlying topographic surface.

Accuracy tests have shown that the AHF system can consistently measure elevation points at the sub-decimeter level. An accuracy test of the AHF was conducted in May 2000 when 17 National Geodetic Survey (NGS) first-order benchmarks were measured at two different helicopter hover heights. The average difference between the AHF measured elevations and the NGS published data sheet values was 3.3 cm. The largest difference was 8.6 cm, and the smallest difference was 0.2 cm. The root mean square error was 4.1 cm. These accuracy test results provide confidence that the elevation dataset being produced meets the ±15 cm vertical accuracy specification.

2. Objectives

The objective of this project is to conduct a topographic survey of Water Conservation Area 2 ( WCA-2). Elevation data will be provided that will be used to parameterize hydrologic models developed for ecosystem restoration efforts. The USGS-developed AHF instrument will be used to collect elevation data points approximately every 400 meters in a grid pattern covering WCA- 2. The same methods that have been developed under the auspices of the USGS Priority Ecosystems Science (PES) Program (formerly the Place-Based Studies Program) will be employed.

3. Scope of Work

The USGS-developed AHF instrument will be used to collect elevation data points approximately every 400 meters in a grid pattern covering WCA-2. This system utilizes GPS to accurately position the hovering helicopter relative to reference base stations. The operator then mechanically deploys a plumb bob to the terrain surface and measures the distance between the ground and helicopter platform. The plumb bob is reeled in after the measurement is made and reset. The helicopter continues along each transect repeating the process to measure an elevation point every 400 miters. These data are then processed to calculate elevation values for each point measured and are referenced to the North American Vertical Datum (NADVD88). It is important to note that the AHF system does not perform bathymetric surveys, so large extents of open water are excluded from using this method. Again, the same methods that have been developed under the auspices of the USGS PES Studies Program will be employed to survey the WCA-2. Lastly, it is also important to note that the cost and delivery dates described herein are best-faith estimates. However, due to the nature of performing fieldwork, delays can sometimes occur because of bad weather, equipment failure, or other unforeseen occurrences. In the unlikely event that a delivery date(s) may slip, the USACE will be notified immediately and any problems will be resolved in the spirit of this agreement and partnership among the parties.

4. Work Breakdown Structure

a. Introduction. The results of the work performed under this statement of work will be used to develop the cumulative finds of the AAT System Status Annual Reports. These annual reports will be used by the AAT to develop a RECOVER Technical Report at five-year intervals, as pursuant to the regulations [Section 385.31 (b)(4)]. This Technical Report presents an assessment of whether the goals and purposes of the CERP are being achieved. The Report will also include an assessment of whether the Interim Goals and Interim Targets are being achieved or likely to be achieved and evaluating whether corrective actions should be considered based on scientific findings of system-wide or regional ecological needs. The Principal Investigator(s) (PI) will be required to work with the AAT Modules Chair to assist in the development of the AAT System Status Annual Report and asked to include their participation as a task in this work breakdown structure. Additionally, the following reporting guidance is offered by AAT to the principal investigator(s):

1) Evaluate Ability to Detect Change - PI Level
a) Describe the results of the power analysis for the sampling design.
b) Determine the minimum detectable difference of the power analysis, and its associated confidence and uncertainty.
c) Describe changes in the MAP sampling design and its implications for the power analysis and the minimum detectable difference.

2) Establish Reference Condition - PI Level
a) Describe the non-MAP data sources, if any, used in the assessment. If non-MAP data were used, did the data meet the guidance criteria? If the non-MAP data were used and did not meet the guidance criteria, provide a rationale to justify the inclusion of the data.
b) Describe how representative the data are in space and time.
c) Describe the approaches used to address measuring variability.
d) Enter the data into the CERP-Zone and update Module Group

3) Measure Change from Reference Condition - PI Level
a) Describe the methods used to estimate the direction and magnitude of change in performance measures from the reference state both annually and back-cast for multiple years.
b) Compare current status of the PM with its desired trend or target.
c) Evaluate consistency of monitoring results with MAP hypotheses.
d) Determine if there are indications of unanticipated events and describe how they are affecting the desired outcome.

4) Annual Integration of Performance Measures (PM) To Evaluate Module Hypotheses -Module Group Level
a) Annually integrate multiple PMs to provide an assessment of module level hypotheses.
b) Describe the direction and magnitude of change in the integrated performance measures, and determine if the changes are consistent with expected responses described in the CERP hypotheses.
c) If the trends do not correspond to expected responses provide scientific explanation.
d) Evaluate progress toward achieving module-level Interim Goals and Interim Targets.

5) System-Wide Performance Evaluation - AAT Level
a) Synthesize findings across-modules and across years to provide a holistic description of the status of the system.
b) Evaluate the results in relationship to; supporting system level hypotheses and achieving system-wide Interim Goals and Interim Targets.
c) Summarize those system-wide changes that are consistent with goals and hypotheses and those that are not.
d) Provide a scientific discussion of why the goals and hypotheses are not being achieved.

b. Task Descriptions.

Task 1 - Establish Geodetic Control Reference Base Stations in WCA-2

Expansion of the USGS AHF geodetic control network into WCA-2 is required. Long-period (i.e. 24 hours) static GPS observations will be completed to survey the necessary geodetic control points required as a prerequisite for AHF operations. Reference GPS base stations are set on these control points during AHF data collection. Data accuracy quality assurance procedures require that the AHF system collect its data within 15 km of a reference base station.

(1) Deliverable - Not applicable. However, this Task must be completed prior to AHF data collection operations described in Task 2 below.

(2) Timeframe - Task 1 is planned for completion in last quarter (Jul - Sep) of fiscal year 2004

Task 2 - Topographic Surveys WCA-2

Topographic surveys will be conducted for WCA-2 using the USGS-developed AHF system. This system utilizes GPS to accurately position the hovering helicopter relative to reference base stations. It then mechanically deploys a plumb bob to the terrain surface and measures the distance between the ground and helicopter platform. The plumb bob is reeled in after the measurement is made and reset. The helicopter continues along each transect repeating the process to measure an elevation point every 400 meters. These data are then processed to calculate elevation values for each point measured and are referenced to the North American Vertical Datum (NAVD88).

(1) Deliverable - Not applicable. However, this Task must be completed prior to the development of digital elevation models described in Task 3 below.

(2) Timeframe - Task 2 is planned to begin last quarter (Jul - Sep) of fiscal year 2004 and completed by second quarter (Jan - Mar) of fiscal year 2005.

Task 3 - Digital Elevation Models for WCA-2

Digital elevation models (DEMs) will be developed from the data collected with the AHF system as described in Task 2 above and delivered to the USACE. The DEMs are digital files containing a grid of elevation data points that are equally spaced about every 400 meters. The DEMs are organized by USGS 7.5 minute topographic quadrangles. The DEMs will also be posted for public dissemination via the South Florida Information Access website (http://sofia.usgs.gov).

(1) Deliverable - Digital elevation models (DEMs) covering WCA-2 developed from data collected with the AHF system in Task 2.

(2) Timeframe - Task planned for completion by June 2005.

5. Project Management

a. SOW Change Control. Changes in the SOW must be requested of the project manager in writing, with supporting justification. Any requested changes in the SOW will require, on part of USGS, submission of an updated project work plan with supporting detail, updated scheduling and budget information. No changes in the SOW will occur without permission from the project manager. Any delays or changes in the work order (WO) scheduling and budget will require consultation with the Adaptive Assessment Team (AAT) of RECOVER. If the original SOW requires any approved changes, USGS must include documentation of these scope changes in the "lessons learned" section of the final project report.

In addition, for multi-year work orders in which the results of each year's work can or will modify what happens in the subsequent years of the work order, the annual report can or will provide a summary of work completed to date and proposed revisions to the future schedule of tasks/deliverables.

b. Data Management. Submission of all data is required for work order closeout. Data formatting, analysis, and delivery will be required to meet all CERP data management standards that can be obtained from the CERP Data Management Program Managers. Any data derived from the SOW will be provided to the AAT at predetermined intervals. All data and results derived from this SOW must be made publicly available or available to the AAT at the end of the work order.

c. Quality Control and Assurance. The work plan will include a quality assurance plan in order to determine which quality control and quality assurance procedures are appropriate for each project (e.g., QASR, FDEP standards). Methods used for each project should be selected based upon the following criteria (if appropriate): cost-benefit analysis, flowchart diagram of the system process, and determination of the best statistical experimental design. The burden of proof of compliance with standardized quality control and assurance procedures is the responsibility of the contractor. In the case where there are not standardized methods for quality control and assurance, the contractor must prove that the suggested methodologies are rigorous. Citation of peer-reviewed and published methods may be used to support this documentation.

d. Status Reporting. Regular progress reports will be made to the project manager as deemed by the task list. Reports will be written (verbal reports are not acceptable). Informal reports regarding status of permits needed for the work order or timely progress of field work or those that describe the completion of specific task elements may be transmitted via email or fax. Reports that include any type of data analysis, datasets, and formal quarterly or interim reports will also be sent via electronic mail; however, signed hard copies with data attached in appropriate format must be mailed to the project manager.