Reviving the River of Grass:  Estimating Operations and Maintenance Costs for Stormwater Treatment

A Guest Post by Paul Walansky, Stanley Consultants

The cost of construction is a significant factor when planning for water management infrastructure projects. With tightening budgets, annual Operations and Maintenance (O&M) costs are more closely reviewed. Today, these costs are given greater consideration in the planning phase as managers are asked to do more with less. 

In response to planning needs for the South Florida Water Management District (SFWMD), a Water Resources Planning Tool was developed to estimate annual operational costs for alternative project configurations and proposed water management features.   This automated tool allows water resources planners to easily estimate operational costs and more effectively evaluate total costs of proposed infrastructure improvements. 

Several steps were performed to develop this tool, including:  a comprehensive review of historical costs, audits, budgets, and salary data; an assessment of SFWMD assets, and a review of staffing and organizational charts. Next, functional activity assessments were performed for information needs matrices, schedules, work plans, technical memos, and cost methodology reports. A Microsoft Access Database was then developed for the SFWMD that incorporated the following features: Stormwater Treatment Areas, Eco-Sloughs, Eco-Reservoirs, Reservoirs, Wetland Managed Areas, and Flow-ways. 

To use the planning tool, data is entered for a proposed feature on the “Estimating Screen” during the planning stages of the project. Based on the type of feature, the O&M tool selects the appropriate formulas and estimates the number of full time employees (FTEs) and O&M costs for: field operations, SCADA / hydro data management, exotic / aquatic vegetation control, aquifer storage and recovery, information technology and telemetry, public use facilities, and water quality, data acquisition and management. 

The O&M Cost Estimating Tool generates a report that allows SFWMD planners to quickly estimate water management O&M costs for the activities associated with a proposed project. Water resources planners can easily estimate O&M life cycle costs, allowing them to quickly evaluate the total costs of proposed infrastructure improvements, and do more planning in less time.

Author:

Paul Walansky, PE

Paul has professional experience since 1999 in the design and construction management of water resources and coastal projects. His engineering background includes inspection and condition assessment of water control structures, niche expertise in Water Resources planning and design, local knowledge of South Florida hydraulics and hydrology, and familiarity with relevant regulatory and environmental requirements. Paul is currently serving as Water Resources Department Manager in Stanley Consultants’ West Palm Beach office.

Flooding causes millions of dollars in damage and even loss of life each year.  Flood preparedness starts with an accurate understanding of the total depth of rainfall that can be expected in storms.  Traditionally, potential storms are quantified according to the total water they will deliver and the probability with which they will occur.  For example, in Tampa, Florida, the storm with 1% chance of occurrence in any given year will deliver approximately 12 inches of rainfall over a 24 hour period (Hershfield, 1961).  Often, this storm is referred to as the 100-year storm, or the storm with a 100-year return period.  As concerns over climate change grow, the fundamental assumption that the size of the 100 year storm remains the same over time is being questioned.  In a new article in the FWJ, Stephen Bourne from the Atkins engineering consultancy explores the question of how Florida storms may change in the future.  Using a combination of general circulation model (GCM) projections of 21^st century Florida weather and libraries of actual historical storms, Mr. Bourne demonstrates a method for predicting the localized impacts of climate change on storm frequency and volume using Tampa, Florida as an example. 

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