Wildlife in riparian ecosystems require specific water quality conditions for key variables such as temperature, nutrients, and dissolved oxygen. Humans alter natural water systems to reduce flood risk and facilitate stormwater drainage. Modifying natural waterways, or hydromodification, in the form of regional retention ponds is gaining popularity as a solution to urban flooding. In this study, we examined and monitored the salinity of an urban retention pond in a Louisiana city park to lay the foundation for a series of necessary studies that address water quality and biological issues associated with flood mitigation tactics. Through field data collection at nine different sites and numerical modeling, we hypothesized that urban retention ponds may accumulate contaminants and pose a risk to biodiversity and public health. Some of the specific factors leading to water quality deterioration are hypoxia, localized chloride pollution, and temperature fluctuations due to sedimentation. The results of this study showed high salinity levels at the bottom of one area of the urban pond that do not disperse throughout the pond. Our results suggest that elevated salinity levels in the pond are likely the result of runoff from a nearby medical complex. Whether the specific source of the saline water is from cleaning operations, medical wastewater, or site construction activity requires further investigation. This study can be used to encourage flood risk managers to consider water quality of urban retention systems in greater detail.