Peace River Cumulative Impact Assessment

In its 2003 session, the Florida Legislature directed the Department of Environmental Protection to assess the cumulative impacts in the Peace River basin.

Introduction

The Peace River drainage basin is approximately 2,350 square miles in area. The river flows about 105 miles from the confluence of the Peace Creek Drainage Canal and Saddle Creek to Charlotte Harbor (see map). Flows from the Peace River are vital to the estuarine health and overall productivity of Charlotte Harbor. Land within the basin has been considerably altered from the natural state by phosphate mining, agriculture, and other development. Additionally, considerable amounts of water are withdrawn each day to support these land uses. Ground water has historically provided the majority of this water, but surface water use for public supply is increasing in the southern part of the basin.

A steady, long-term decline in Peace River flows has been observed since the early-1960s. The causes of the decline are complex. Average annual rainfall over the last 30 years is about five inches/year lower than in the previous 30 years. Ground-water withdrawals for public supply, agriculture, and mining have lowered the potentiometric surface of the Floridan aquifer since the early-1930s which has reversed the hydraulic gradient between the river and underlying confined aquifers. This has caused gravity drainage of the river into sinkholes in the upper part of the basin.

The cumulative effects of land use changes due to urbanization, agriculture, and mining can change stormwater runoff and baseflow contributions to the river. Drainage of wetlands through ditching and canal construction can affect surface water storage and runoff patterns. Historic phosphate mining and reclamation of mined lands can alter the timing and magnitude of runoff, surface water storage, recharge, and evapotranspiration. All of these factors contribute to changes in hydrology and ecology within the Peace River basin.

To address the potential effect of these activities in the basin, the Florida Legislature directed the Florida Department of Environmental Protection (DEP) in its 2003 legislative session to assess the cumulative impacts to the Peace River basin. This study, called the Peace River Cumulative Impact Assessment, will form the basis for preparation of a resource management plan. The subsequent resource management plan (not a part of this study) will identify regulatory and non-regulatory means to minimize future impacts for the basin.

For additional information on background conditions of the Peace River basin, view or download the PDF document Background Information on the Peace River Basin .

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