Statistical Changes of Lake Stages in Two Rapidly Urbanizing Watersheds

Abstract

Understanding changes induced by watershed urbanization is integral to developing an effective long-term management strategy. In this research, the authors study statistical changes of lake water surface levels in two urbanizing watersheds by evaluating serial change in time series parameters, autocorrelation, and variance as well as by developing a regression model to estimate weekly lake level fluctuations. The authors fit a seasonal integrated autoregressive moving average model to lake levels over subperiods of the data record to identify trends in parameter values. The authors fit the regression model with rainfall, lake stage, and temperature components for pre-urbanized and urbanized time periods to identify changes in baseflow. The lakes were located in Pasco County, Florida, USA and have not been significantly influenced by changes in rainfall patterns, pumping, surface water extraction or physical modification. Furthermore, the lakes exhibit consistent watershed urbanization and have sufficiently long and complete records. Based upon the research, the authors reach the following general conclusions about lakes in urbanizing watersheds: (1) the statistical structure of lake level time series is systematically altered, (2) in the absence of other forcing mechanisms, autocorrelation and baseflow decrease, (3) the presence of wetlands adjacent to lakes can offset the reduction in baseflow. These conclusions can be applied globally to similar regions that consist of lakes undergoing urbanization in flat, humid, shallow water table environments with wetlands. Furthermore, the methodology utilized can be applied at lakes in both similar and dissimilar environments to those studied in this research.

A Spatially Distributed Groundwater Metric for Describing Hydrologic Changes in a Regional Population of Wetlands North of Tampa Bay, Florida, from 1990 to 2015

“…This downward trend in the highest potentiometric surface elevations could be a regional expression of less in ltration to groundwater due to an increase in impervious surfaces in the study area (Weng and Pu 2013). A study by Paynter et al (2011) found that urbanization reduces groundwater ow to lakes in this same area. Increasing groundwater withdrawals outside of well elds over the same period probably contributed to this effect as well (Geurink and Basso 2013, Fig.…”

Operational Prediction of Groundwater Fluctuation in South Florida using Sequence Based Markovian Stochastic Model

“…The wetland serves to temporarily retain excess surface water during the wet season and releases it to streams during the dry season (Paynter et al 2011). However, because of the anthropogenic interference through canal dredging, channelization, and drainage it has resulted in fast movement of water to the downstream side entailing a risk of disconnectivity of groundwater dependent wetlands during extended dry seasons (Ali 2009).…”