Bloetscher, Frederick

Flooding disasters pose a significant threat worldwide, with 2022 seeing them as the most common type of disaster. In the U.S. alone, four flooding disasters in 2023 cost more than $9.2 billion. Coastal urban areas face increasing threats from flooding disasters due to rising sea levels, changing precipitation patterns, and intensifying extreme weather events. This study focuses on Central Beach, Fort Lauderdale; the area's unique geographical, environmental, historical, and socio-economic characteristics make it a prime candidate for this analysis. The research objective is to comprehensively examine the factors contributing to water-related vulnerabilities of developed properties in Central Beach and assess localized impacts using regional models. The methodology involves developing probabilistic flood maps using GIS tools and the Cascade 2001 routing model. The flood scenarios consider groundwater table rise, extreme rainfall, high tides, storm surge, and sea level rise. Results indicate significant inundation risks, particularly for commercial and mobility infrastructure, under storm surge and sea level rise scenarios. The analysis highlights the importance of targeted mitigation efforts to protect these areas and reinforce resilience against future flooding events. The findings contribute valuable insights for policymakers, urban planners, and stakeholders, emphasizing the need for comprehensive strategies to mitigate flood risks in coastal urban areas.

A comparative risk assessment of wastewater disposal methods in southeast Florida has only been performed once and it was over 20 years ago. Since then, methods has changed and research have been developed. This study follows the methods used in the 2000 study, and assesses the following disposal methods: ocean outfalls, deep injection wells, surface water discharge, reuse for non-potable applications, indirect potable reuse, and direct potable reuse. This assessment assembled a team of qualified experts to complete a modified delphi survey to assess the human risks of wastewater disposal methods. Using the delphi results in a Bayesian Assessment Model, this assessment found that deep injection well and direct potable reuse were the disposal methods with the least risk.

This research aims to develop a large-scale locally relevant flood risk screening tool, that is, one capable of generating accurate probabilistic inundation maps quickly while still detecting localized nuisance-destructive flood potential. The CASCADE 2001 routing model is integrated with GIS to compare the predicted flood response to heavy rains at the watershed, subwatershed, and municipal levels. Therefore, the objective is to evaluate the impact of scale for determining flood risk in a community. The findings indicate that a watershed-level analysis captures most flooding. However, the flood prediction improves to match existing FEMA flood maps as drill-down occurs at the subwatershed and municipal scales. The drill-down modeling solution presented in this study provides the necessary degree of local relevance for excellent detection in developed areas because of the downscaling techniques and local infrastructure. This validated model framework supports the development and prioritization of protection plans that address flood resilience in the context of watershed master planning and the Community Rating System.

CASCADE 2001 is a multi-basin flood routing program used in areas of flat terrain. CASCADE was used for different situational elements including the Florida Keys, Broward County, and Pensacola. The goal for this screening tool was to create flood inundation watershed mapping for the Florida Division of Emergency Management (FDEM). After showing the risks of flooding that could occur in Florida, the thought of how useful CASCADE can be in other environmental conditions. The Rocky Mountains were selected to show the effect of flood inundation that can be mirrored in an opposite condition from prior experimentation. We chose to test this program in an area with mountainous terrain like the region of Grand Lake, Colorado.
Rainfall, in collaboration with groundwater tables, ground soil storage and topography have the most effect on the CASCADE modeling program. Effects that were not used in the Florida models but added for Grand Lake included snowmelt. Snowmelt in the Rocky Mountains affects the flow of the Colorado River causing excess discharge that flows throughout the valleys and into Shadow Mountain Lake. WINSRM was a recommended model that could be used to simulate snowmelt during different months of Colorado’s spring season. The effects of snowmelt and rainfall flooding can be compared in relation to each other.

Coastal basins are particularly vulnerable to flood under multivariable conditions, such as heavy precipitation, high sea levels, tropical storm surge and rainstorms. These conditions should be considered to assess and manage flood risk better. In this research, a means to develop a watershed level screening tool to identify areas with potential for flooding due to high tides, rainfall events, sea level rise and combinations of all the cases was developed and compared to FEMA maps. The goal of the screening tool is part of a larger effort with respect to watersheds funded by the Florida Division of Emergency Management to enable local communities to reduce flood insurance costs through mitigation and resiliency efforts by means of risk assessment was undertaken. For this purpose, readily available data on topography, ground, and surface water elevations, tidal data for coastal communities, soils, and rainfall data were collected from the South Florida water management district, USGS, and NOAA. Firstly, using elevation data, soil data, and the Spatial Analyst tool, Arc-Hydro tools of ArcGIS, the drainage network, and soil storage capacity were determined. These results and rainfall data acted as inputs for Cascade to calculate the headwater height for all the cases for the selected basins. Using these headwater heights, several different probabilities of inundation were determined. This study will help manage and mitigate vulnerable areas and act as a tool to permit local agencies to develop means to address high-risk properties.

Flood risk analysis is the instrument for utility managers to create a sound strategy and adaptation plans into their communities. Local municipalities are being continuously challenged every year by the impacts of climate change. The need to develop a screening tool to analyze watersheds and find risk areas is the goal of this research. Open source high-quality data is allowing climate scientists to create innovative ways to study watersheds when performing spatial analysis for inundation areas. The development procedures for a screening tool involved combining readily available data on topography, groundwater, surface water, tidal information for coastal communities, soils, open space, and rainfall data. All efforts to help develop a planning level framework that allows investigators to target the optimal set of outcomes for a given community. This framework appears to be viable across cities that may be inundated with water due to sea-level rise, rainfall, runoff upstream, and other natural events.

Safe drinking water is paramount to a healthy society. Close to a hundred contaminants are regulated by the government. Utilities are using chloramines to disinfect water to reduce harmful byproducts that may present themselves with the use of chlorine alone. Using chlorine and ammonia to disinfect, ammonia oxidizing bacteria can present themselves in an unsuspecting utilities distribution network.

This pilot study was conducted to determine if an Electron Magnetics Oxygen and Hydrogen (EMOH) device can increase the dissolved oxygen (DO) concentration of a residential surface water. By using EMOH, DO concentration will increase and allow bacteria to remove the substrate that creates blue-green algae for which the City of Boynton Beach (City) receives complaints. Those complaints center on odors and the visual appearance of the ponds. The study was conducted in-situ at the INCA Pond system in the City of Boynton Beach, Florida with data collection taking place bi-weekly, using surface aeration techniques. Water sampling was conducted in the INCA Pond system via a handheld water sensor. Primary variable monitored included: water temperature, barometric pressure, DO concentration, and DO saturation (DOSAT). Biomass of dead algae at the bottom of the pond was also monitored to determine if increased DO concentration aided the biological digestion of the organic matter. Data analysis shows that exposure to EMOH treatment allowed the relationship between DO and temperature to change from a negative correlation (the expected relationship) to a positive trend. Furthermore, pressure and DOSAT became less correlated after exposure to EMOH effluent. In all, EMOH was shown to be an effective means of treating hypoxic pond water. The optimal EMOH effluent discharge is determined to be deep in the subject pond. Backed by research on the surface-air water and bubble-water oxygen transfer coefficients, DO concentration in the subject pond was 110% higher when effluent was directed down toward the floor of the pond.

The South Florida Water Management District (SFWMD) is an agency which relies on a
network of nearly 300 rain gauges in order to provide rainfall data for use in operations,
modeling, water supply planning, and environmental projects. However, the prevalence
of convective and tropical rain events in South Florida during the wet season presents a
challenge in that the current rain gauge network may not fully capture rainfall
demonstrating high spatial variability. NEXRAD (Next Generation Radar) technology
offers water management officials the advantage of providing a spatial account of
rainfall, although the relative quality of radar rainfall measurements remains largely
unknown. The intent of this study is to examine the relationship between gauge-adjusted
NEXRAD data and corresponding rain gauge measurements in order to assess the relative
performance of radar and rain gauge technologies for a variety of different conditions.

This study evaluated the technical feasibility o f increasing the typical water
recovery of a pilot scale membrane system (85-90%) to 97% by treatment of
nanofiltration concentrate with low-pressure reverse osmosis. The study used Biscayne
aquifer water (freshwater), and determined that it may be technically feasible to increase
the recovery up to approximately 95% when the RO flux is —10 gfd, the feed water pH is
reduced to -6.1 with H2 SO4 , and antiscalant in the NF process. The tested membranes
showed stable and similar performance under the pilot conditions. However, pilot tests
were sensitive to pH variations (pH>6.2). The main barrier for increasing the water
recovery was fouling caused by iron, carbonate hardness, and iron bacteria. A
preliminary cost analysis showed that there is an apparent econom ic advantage when the
recovery is greater than 90%. Estimated water cost at 95% recovery is $1.99 compared
with $2.69 at the typical 85% recovery.