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The Balmoral Group

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Stormwater Management

The Balmoral Group specializes in hydrologic and hydraulic engineering. Our professionals provide consulting services in the areas of:

  • stormwater collection and treatment;

  • complex hydrologic analysis and hydraulic design;

  • drainage design,

  • and flood studies.


Since its founding, the firm has established a reputation for its expertise by applying the latest technology in hydrologic modeling and GIS analysis to complex drainage design.

The Balmoral Group is also the U.S. distributor of CatchmentSIM™ (, a stand-alone 3D GIS application that is used to automate the setup of hydrologic models. 

Alternatives Analysis for the Powell Watershed, Hernando County

Southwest Florida Water Management District

The Balmoral Group performed the alternatives analysis for the Powell watershed in Hernando County, FL. Extensive coordination was required with SWFWMD, Hernando County, and the project assistance consultant to document design decisions and methodology processes. Tasks included developing the project plan, assessing the Level of Service (LOS), developing a surface water resources assessment (SWRA), and evaluating best management practices (BMPS) for the 7.4 square mile Powell watershed in Hernando County, Florida. Watershed-specific Model Builder tools in ArcGIS were created and implemented to aid in the quality control of specific parameters. As part of the BMP evaluation, fourteen BMP locations were identified and coordinated with SWFWMD and Hernando County on site selection following a county-tailored ranking analysis. Five BMP locations were selected to develop conceptual schematics, perform routing calculations, evaluate the cost-benefit ratio, and determine the permitting impacts. The review of basins included Wiscon, Bystre Lakes, Spring Hill Lakes, Squirrel Prairie, and Crews Lake Outlet.

Jack Creek Watershed Management Plan, Highlands County

Southwest Florida Water Management District

The Balmoral Group was tasked with the Project Development, Watershed Evaluation, and Floodplain Analysis for the 70 square mile project area which includes three watersheds, Sebring Annex, Jack Creek, and Lake June-In-Winter in Highlands County, FL. The proposed modeling level of detail for this effort focused on the known areas of flooding, which occurred during Hurricane Irma. Task efforts included developing the Project Plan which recommends using ICPR v4 and HEC-RAS to develop the bridge rating curves. A Watershed Evaluation was performed for this project which included initial GIS processing using CatchmentSIM, field reconnaissance and engineering-level survey using Trimble Geo 7x (for horizontal and vertical accuracy), and model parameterization. A final Watershed Evaluation report was prepared in order to perform the floodplain analysis efforts. A full model was developed in ICPR v4 which utilized Hurricane Irma and Hurricane Frances as the calibration and verification storm events. A Floodplain Justification report was prepared as part of the final deliverable. This modeling effort will be utilized to evaluated proposed conceptual BMP alternatives in order to alleviate flooding in the areas of concern.

CR 159 Bridge over Attapulgus Creek, Gadsden County

Florida Department of Transportation District Three

The Balmoral Group was tasked with the preparation of the Bridge Hydraulics Report (BHR) and Drainage Design of the CR 159 bridge over Attapugulus Creek located in Gadsden County of Tallahassee, FL.  The BHR analysis included establishment of minimum low chord elevations, preparation of scour estimates, and quantifying the impacts that the bridge will have on existing flood behavior. This project included an onsite detour road and bridge which was incorporated into the hydraulic modeling.  Drainage calculations were prepared for proposed roadside ditches and ditches for MOT phases.  Other tasks included erosion control and determination of wetland impacts. The hydraulic analysis showed that the proposed bridge does not increase the water surface profile for the 50, 100, and 500 year events at any locations upstream or downstream of the bridge.  Based on the outcomes of the BHR, the proposed bridge will improve the existing hydraulic characteristics of the river for the design 50 year, 100, and 500 year events as well as lower storm events.

US 90 (SR 10) from Glover Lane to SR 87S PD&E, Santa Rosa County

Florida Department of Transportation District Three

The Balmoral Group was responsible for providing drainage design services for the US 90 (SR 10) improvements from Glover Lane to SR 87S. The project consisted of evaluating the drainage improvements necessary to accommodate widening from a two-lane divided rural section to a four-lane divided urban section with bike lanes and sidewalk. The western portion of the project extends through the City of Milton which has a complex storm sewer network which ultimately discharges to the Blackwater River. The eastern portion of the project accepts runoff from low lying areas along the south of US 90 and is constrained by the CSX railroad and Prince Philip airport on the north. A detailed ICPR model was created for the project area east of Blackwater River in order to quantify the impacts of the proposed improvements on the existing floodplains. Responsibilities included providing a pond siting report, bridge hydraulic technical memorandum, and a location hydraulics report.  The Pond Siting Report consisted of design considerations for each pond site location. Each pond site location included hydraulic data, hydrology (landuse cover, soil types, seasonal high water elevations, etc.), environmental impacts, wetland impacts, impacts to protected conservation areas and species, economic factors, cost of right-of-way (ROW) acquisition and impacts to cultural resources. The Bridge Hydraulic Technical Memorandum was compiled to provide an analysis of existing hydrologic data, preliminary estimates for low member elevations and bridge lengths for three bridges based upon existing analyses and data. The Location Hydraulics Report presented the existing condition of each of the ten existing cross drains and the hydraulic analysis for the existing and proposed cross drains.

Wekiva Parkway 429-203, Orange County


Central Florida Expressway Authority

The Balmoral Group Project performed the stormwater management design for the 2.4 mile stretch of Wekiva Parkway between Ponkan Road and just north of Kelly Park Road through Orange County. The existing terrain model was created using CatchmentSIM from existing LiDAR data, field survey, and previously permitted information in order to effectively model the closed depressions. ArcGIS was used to integrate the subcatchments generated by CatchmentSIM with the landuse cover and soil layers to development an overall basin map. Hydrology parameters were analyzed using ICPR to create an overall existing conditions model and post-development conditions model. The Lake Victor FEMA mapped floodplain was analyzed to establish the BFE. The post-development model demonstrated no impacts to the existing 100-yr stage. Permitting efforts were coordinated through FDEP

Orange County Barry Street Drainage Improvements Analysis

Orange County

This project consisted of Barry Street Drainage Improvements Analysis, located along SR 50 near the Central Florida fairgrounds in Orange County, FL. The proposed work consisted of completing the Phase I analysis, which included data collection, existing conditions analysis, alternatives analysis, coordination with South Florida Management District (SFWMD) and the Florida Department of Transportation (FDOT), and the compilation of a technical memorandum presenting the findings. Additional tasks included analyzing the original 2003 Barry Street Drainage Analysis and the existing stormwater system to identify bottlenecks in the drainage system, evaluating improvements to the onsite conveyance system, evaluating the SR 50 outfall drainage system and the feasibility of improvements that could reduce flooding within the project area, and, evaluating the feasibility of an upsized outfall connection with Old Winter Garden Road. Sub consultant to Inwood Consulting Engineers, Inc. Project is currently in final review.

Suncoast Parkway Two (SR 589), Section Two, Citrus County,


Florida Turnpike Enterprise

This project consisted of a 4.8-mile section of the proposed Suncoast Two Parkway that lies in the Coastal Rivers Basin of the SWFWMD.  The unique conditions of this roadway segment required a detailed modeling of the existing conditions so that roadway impacts could be properly analyzed.  The availability of LiDAR data and watershed management plans for this project allowed for the use of the Hydrologic Software “CatchmentSIM” and ArcGIS to efficiently evaluate over 100 basins comprising approximately 30 square miles.  The dry closed basins were analyzed using the Green-Ampt method for runoff calculation and ICPR including percolation for peak stages. The project includes one significant interchange at SR 44 where soil confining layers and perched water tables required detailed evaluation of the stormwater approach. The rolling terrain required detailed review of the roadway cross sections and detailed design of the roadside ditches in order to prevent erosion in the sandhills. The Balmoral Group was also responsible for the design of the collection system and plans production which included 16 dry retention ponds and several ditch treatment areas that span across 2 major SWFWMD watersheds. Drainage design responsibilities also included a cross drain analysis of the proposed multi-use trail that runs along the Suncoast Parkway.