WEDNESDAY 7:30 - 8:15 a.m.: BREAKFAST SERVED
7:45 - 8:15 a.m.: GOLD SPONSOR PRESENTATION
8:15 - 8:30 a.m.: BREAK
WEDNESDAY 8:30 - 9:00 a.m.
Watershed Planning Room
Brian Fairchild
HDR
Kalyn Bishop
HDR
Join us as we discuss what’s new to using HEC-RAS in 2025! This presentation will include a live demonstration of RAS 2025’s alpha build and the new pipe network modeling features in the most recent full-release of HEC-RAS Version 6. We will finish off the presentation with news and updates on topics like 2D floodway modeling, no-rise analysis, and any other changes in the regulatory scene that we have witnessed.
Civil Works Room
Carl Brooks
City of Harrisonville
Carl Brooks
Eight miles to the north of the city lays Lake Harrisonville, Harrisonville’s one and only water source. Lake Harrisonville built in the early 1970’s is a 6,990 acre-ft lake, with a dam, and a raw water intake pumping station which pump into a 12-inch raw water transmission main to the Water Treatment Plant in Harrisonville. Bolstered by visionary leadership and a proactive operations and maintenance staff, the city recently completed the Lake Harrisonville Primary Spillway Repair Project Missouri DNR Dam ID No 200077, that included a new Riser Intake Structure and a new Pipe Outfall. With not so easy access from MO Hwy 291 and MO Hwy 58 lays the lake and dam that is supported by a watershed drainage area of 8,560 acres, enabling this as a valuable city resource and enticing future generations of commercial and residential developers.
The MDNR and the City worked with Anderson Engineering (now known as OWN Engineers) to create improvements to replace the current lake morning glory concrete overflow structure transitioning to an 8-foot diameter asbestos lined corrugated metal pipe. The OWN team provided complete design professional services – including the new riser reinforced concrete intake structure, the 6-foot diameter outfall slip-line pipe, plunge pool improvements, hydraulics, survey, environmental permitting, public involvement, construction phase services and more. With the age and condition of the overflow structure and outfall pipe, MDNR had given the City only a one-year renewal of Registration Permit R-337 in 2020, but the City’s initial budget of $1M was not approved in 2021 and not approved in the city’s budget until 2022.
The project grew out of a cooperative effort between MDNR, City and Anderson Engineers study funded by the City. The study showed a need for a new riser intake structure ana outfall pipe that was the critical first step in improvement. City staff and Anderson staff next prepared the plans, specification and cost estimate for the project. After the City of Harrisonville advertised and bid on the project, Harrisonville knew that the proposed project was not going to work as the low bid was 40% higher that the entire overall budget. Harrisonville staff considered a “Value Engineering” Labyrinth Chute Spillway Design, but to no financial improvement success. Then to the surprise of the Harrisonville staff, the MDNR Dam and Safety Program Department, recommended that the Harrisonville staff contact the Multi -Purpose Water Resource Department within MDNR and make application for a Multi -Purpose Water Resource Department grant application.
Harrisonville received a $1.2M grant and a $700,000 loan to be paid back at 0% interest over the next twenty years. Our project finances were solved. and with funding in hand, City staff selected Legacy Underground Construction to construct the project. The team of MDNR, City staff, OWN Engineers and Legacy Underground Construction moved the project from concept study to final design to construction.
MS4/CSO Programs & Standards Room
Andy Sauer
Burns & McDonnell
Andy Sauer
Stormwater management is the general term used to describe the methods and requirements to mitigate the impacts caused by urban development. Urban development impacts the land surface by altering grades, adding impervious surfaces, installing collection systems, and constructing enclosed pipes that discharge directly to the nearest stream. Historically, stormwater management criteria do not take a systematic approach considering how actual rainfall events occur; how excess rainfall becomes runoff; the volume of runoff; and/or the different routes stormwater can take. Furthermore, these spatial and temporal complexities are not considered, simplifying design calculations down to one or two peak flow rate calculations. This has resulted in urban stormwater systems that are collecting and routing stormwater downstream with little or no volume control. This approach has resulted in efficiently collecting excess rainfall up to the peak design flow rate passing all excess stormwater volume downstream. However, with changing rainfall patterns that are becoming more intense and more frequent the impacts downstream are become more acute. In urban areas we are having more flash flooding, streams are eroding impacting private property and public infrastructure like sanitary sewers and bridge abutments, and water quality is degrading. Stormwater management needs to do more.
This presentation will provide examples of why stormwater management needs to do more and how solutions can be more affordable if they manage more of the runoff volume than just passing it downstream. Newer, more advanced stormwater computer models are now available to simulate real rainfall events using digital topographic information to more accurately simulated runoff conditions demonstrating existing and proposed conditions. Data collection, mapping, and real-time controls can be implemented to evaluate the existing system, display flood inundation, and monitor flow and flood depths in real-time. Finally, examples will be provided that when urban runoff volume is collected and controlled through retention and detention practices the benefits downstream can be improved saving communities both short-term and long-term costs. Stormwater management can do more.
WEDNESDAY 9:00 - 9:30 a.m.
Watershed Planning Room
(no session)
Chad Johnson
CDM Smith
Ian Fannin-Hughes
Johnson County Stormwater Management Program
The Johnson County StormWatch ALERT Flood Warning System monitors streamflow, rainfall, and temperature across the County. It includes 90 rain gages, 70 stream level sensors, and other weather data measurements. To better understand occurrence of extreme storms in the County, an in-depth analysis of rainfall and streamflow was conducted for 11 principal storms between 2004 and 2024. For each storm, a narrative discussion of each event was prepared, along with summaries of streamflow and rainfall maxima across the County. Tables and maps were prepared presenting rainfall maxima at durations from 5 minutes to 7 days for StormWatch gages, as well as for National Oceanographic and Atmospheric Administration (NOAA) gages at Johnson County Executive Airport and New Century AirCenter. Average recurrence interval statistics were calculated from NOAA Atlas 14 frequency estimates. Storm total precipitation estimates for the NOAA Kansas City NEXRAD (Next Generation Weather Radar) were prepared for storms through 2020. For two storms in 2024, NOAA Multi-Radar Multi-Sensor (MRMS) peak hour quantitative precipitation estimation maps were prepared. Stream gage peak discharge statistics were developed for 10 Johnson County sites based on U.S. Geological Survey (USGS) discharge measurements and frequency estimates from the USGS StreamStats database.
The heaviest rainfall occurred on July 11, 2006 and August 21, 2017. Both storms had 6-hour ARIs close to 50 years and 24-hour ARIs exceeding 10 years at New Century AirCenter; slightly less rainfall fell at Johnson County Executive Airport. All the streams recorded between seven and eleven 2-year or larger events over the 21-year period, reasonably in line with the expected value of 10 such events at each location. However, the Indian Creek gage at Overland Park recorded five 10-year events, while the Indian Creek at Leawood gage recorded seven 10-year events. This may indicate that the statewide regression formulas used to estimate peak discharges for Indian Creek do not provide appropriate peaks on this stream or that the discharge rating curves need revision.
Civil Works Room
Brad Schleeter
Olsson
Brad Schleeter
The focus of this presentation is the process of preparing a Preliminary Project Study (PPS), designing the recommended alternative, and construction of improvements on Tomahawk Creek Parkway in Leawood, Kansas. The study area for the PPS was a 1.6 mile stretch of Tomahawk Creek Parkway, between Roe Avenue and College Boulevard. This roadway section runs parallel to Tomahawk Creek and experiences frequent roadway flooding, particularly the northbound lane of the parkway, during high water events in Tomahawk Creek. Approximate flood depths in the lowest sections of the Parkway have been estimated at over 5-feet deep during several significant rain events in the past 20 years. This City of Leawood was looking to leverage both Johnson County Stormwater Management Program (SMP) funding and Federal transportation funding to reduce the roadway flooding depths and frequencies, and improve and upgrade this section of Tomahawk Creek Parkway.
This Tomahawk Creek Parkway PPS was completed in February 2023 and was the first PPS completed using the Johnson County SMP’s risk-based flood reduction methodology that came out of the Johnson County Watershed Master Plans updates that were completed in 2021. This new risk-based approach gave freedom within the PPS process to evaluate a range of potential solutions that balanced flood risk reduction with project cost.
This presentation will take a deep dive into the project background, including the priority risk focus area designation for this segment of Tomahawk Creek Parkway with the Watershed Master Plan, the evaluation of a range of project solution types, and how the County’s Risk Integrated Project Prioritization (RIPP) allowed Olsson to evaluate the risk reduction for various solution types that did not necessary eliminate roadway flooding, but rather reduced the roadway flood risk to varying degrees.
The preparation of the PPS did not overlap with the completion of the 2-Dimensional (2D) HEC-RAS model for Watershed 2 (Indian and Tomahawk Creek watershed), however, during the project design process, the recommended project solution from the PPS was loaded into the completed 2D model to evaluate the flood risk reduction in this model. This presentation will include a comparison of the PPS model and 2D modeling results, and how differences between these two models influenced the ultimate project design. Based on this 2D model analysis, the City decided to revise the project design to increase the flood risk reduction as determined by the 2D model.
MS4/CSO Programs & Standards Room
Kathy Gee
OptiRTC
Greg Hoffman
Center for Watershed Protection
The Draft MARC-APWA Regional Stormwater Standards herald a significant advancement in urban water management, establishing runoff volume reduction as a foundational principle for creating resilient infrastructure and protecting water quality across the Kansas City metropolitan area. This presentation will delve deeply into this core tenet, illustrating how the new standards champion a comprehensive strategy to minimize stormwater runoff at its source. We will then explore how this crucial runoff reduction principle is effectively addressed through a diverse array of green stormwater infrastructure (GSI) practices and the innovative application of Continuous Monitoring and Adaptive Control (CMAC) systems.
The MARC-APWA standards emphasize that effective runoff reduction extends beyond a singular reliance on infiltration. We will highlight how GSI practices that operate through various mechanisms, such as green roofs promoting evapotranspiration and detention, or underdrained bioretention systems and permeable pavements that detain and filter water prior to controlled release, are integral to fulfilling the runoff reduction principle. These practices, often overlooked in simpler infiltration-focused models, play a vital role in the holistic volume reduction strategy envisioned by the regional standards.
The presentation will then specifically address how Continuous Monitoring and Adaptive Control (CMAC) offers a powerful mechanism to ensure the runoff reduction principle is not just a design aspiration but an operational reality. CMAC systems, through their use of real-time sensors, weather predictive analytics, and automated control elements, empower GSI practices to dynamically optimize volume capture. By actively managing storage and release from these systems, CMAC directly serves the runoff reduction principle by minimizing downstream discharges. Furthermore, by tailoring operations to current and forecasted conditions, CMAC ensures that GSI practices achieve their maximum potential contribution to overall runoff reduction, aligning their performance with the requirements of the new standards. A key aspect of the runoff reduction principle is accountability, and CMAC systems provide quantifiable verification of this reduction by delivering continuous, verifiable performance data from these actively managed systems. Finally, CMAC allows for adaptive management strategies within these systems, ensuring they consistently perform to meet runoff reduction targets despite variability in rainfall patterns or evolving site conditions.
By incorporating diverse GSI practices and leveraging the intelligence of CMAC, municipalities and developers in the Kansas City region can more effectively and efficiently achieve the runoff volume reduction goals set forth in the new standards. This presentation will provide insights into the practical application of these principles, showcasing how a comprehensive and technologically advanced approach to stormwater management can lead to more resilient communities and healthier watersheds.
WEDNESDAY 9:30 - 10:00 a.m.
Watershed Planning Room
Jeff Doudrick
HNTB
Jeff Doudrick
East Baton Rouge Parish embarked on an ambitious effort to rethink stormwater management, beginning with a visioning document that laid the groundwork for one of the most comprehensive stormwater master planning processes in the region. This presentation will walk through each major phase of the East Baton Rouge Stormwater Master Plan (SMP), starting with the development of an Implementation Plan and advancing through robust data collection, hydrologic and hydraulic modeling, and prioritization of capital improvement projects. Public engagement played a central role, with input gathered through a dedicated website, mobile app, and dozens of public meetings across the Parish.
As the plan evolved, the team worked closely with Parish staff to modernize stormwater policy through proposed ordinance updates, including the development of conveyance zones to guide safer development in high-risk areas. With the SMP and Capital Improvement Plan documents complete, implementation is now underway. This includes technical support on grant applications, reviews of offsite drainage impacts for proposed developments, and ongoing model updates to support future decision-making.
Attendees will gain a detailed understanding of how this collaborative, data-driven process was structured and executed, from early planning through long-term implementation, and how the approach can be tailored to meet the needs of other urban communities.
Civil Works Room
(no session)
MS4/CSO Programs & Standards Room
Dirk Hudson
Advanced Drainage Systems
Dirk Hudson
Managing stormwater is increasingly presenting a variety of challenges to urban environments. Many communities in the Kansas City Metro area are dealing with CSOs and/or federal mandates to mitigate the impacts of stormwater. Fortunately, the most recent APWA Section 5600 Design document assists with identifying Green Stormwater Infrastructure BMPs and calculating stormwater variables such as Required Retention Volume (RRV).
While these APWA Section 5600 changes focused on right-sizing our infrastructure requirements to storm events, this presentation is focused on right-sizing your Green Stormwater Infrastructure devices to the project site. The best way to ensure performance would be through using past treatment data from the laboratory and current field installations with testing known. We shall investigate a series of projects installed in Overland Park, KS to view how Green Stormwater Infrastructure has functioned over the years on this site. In addition, the importance of treatment characteristics for performance sizing will be highlighted. Those parameters include the particle size distribution, influent and effluent rates, and the hydraulic loading.
To have the hydrology sized properly per APWA Section 5600 is Step 1 of right-sizing the project. Step 2 includes having the hydraulics of your proposed engineered design solution to be right-sized using known site data, past Green Stormwater Infrastructure field data, and/or nationwide vetted laboratory data from a renowned organization, such as New Jersey Department of Environmental Protection.
This open discussion with conference participants will highlight a variety of local, regional, and national urban research and case studies demonstrating how water quality and infiltration techniques offer highly sustainable and resilient water management solutions. It will also verify how long-term performance is achieved with minimal maintenance and oversight.