(Credit to the Illinois State Water Survey for the graphic below)

Introduction 

Recharge is the term used to describe how an aquifer gains water from the surface (precipitation, rivers, etc.) or the subsurface (other aquifers). When an aquifer is recharging, groundwater levels rise to be closer to the ground surface, and artesian pressure generally increases. The PCGCD is tracking factors related to recharge such as precipitation (rainfall, snow, etc.) and water levels in water wells.

Panola County is in the outcrop of the Carrizo-Wilcox aquifer, also referred to as the recharge zone of the Carrizo-Wilcox. This means that some of the geologic formations which store groundwater are oriented so that they intersect the ground surface in such a way that they are “open ended” and can receive water from the surface. This is good news for us in that the aquifer will recharge faster than in non-outcrop areas, but it is bad news in that there is a higher risk of groundwater contamination from surface sources.

In recent hydrogeological studies, however, the District has determined that many wells in the county display water level changes that represent a confined aquifer (groundwater under pressure).  Also, flowing springs in the county are another indicator of confined aquifer conditions.  So it appears that the Carrizo-Wilcox here is a hybrid of the two types.  This means that when groundwater levels fluctuate, it probably is due to changes in aquifer pressure rather than rapid emptying or filling of the aquifer.

(Credit to the Illinois State Water Survey for the graphic below)

Rain Gauges

The PCGCD has 5 rain gauges in Panola County, located in Deadwood, DeBerry, Rock Hill, Gary, and Carthage. At the end of each month, the precipitation recorded by each gauge is averaged to give an approximate rainfall amount for the county. In the graphs below, the data recorded by the PCGCD are compared to what is reported by the National Oceanic and Atmospheric Administration (NOAA) for our area.

2011 Cumulative Precipitation

2012 Cumulative Precipitation

2013 Cumulative Precipitation

2014 Cumulative Precipitation

2015 Cumulative Precipitation

2016 Cumulative Precipitation

2017 Cumulative Precipitation

Monthly Precipitation

Monthly Precipitation Since 2011

NOAA Website

In the link below is a graph of the annual cumulative precipitation totals for the Carthage weather station, dating back to the 1950s, courtesy of the Southern Regional Climate Center. This graph provides interesting insight into our local wettest years, driest years, and long-term patterns.

Historic Annual Precipitation – Carthage

 

Drought Monitoring

Drought is a major influence on all water sources. When precipitation becomes sparse, surface water and groundwater conservation remains crucial in meeting water demands. Provided below is a link to the U.S. Drought Monitor for Texas, a useful tool for tracking state and local drought conditions week-to-week.

 

Drought Monitor

Current Status of Panola County:  No Drought

The U.S. Drought Monitor is produced through a partnership between the National Drought Mitigation Center at the University of Nebraska-Lincoln, the United States Department of Agriculture, and the National Oceanic and Atmospheric Administration.

Monitor Wells

The PCGCD currently has 14 monitor wells spaced throughout the county which are used to measure water levels once each month. The Texas Water Development Board has 16 monitor wells in Panola County, all of which have been absorbed by the District in order to supplement our database. Below are links to graphs showing the average change in water level county-wide each month and each year.

PCGCD 2011 Monthly Monitor Wells

PCGCD 2012 Monthly Monitor Wells

PCGCD 2013 Monthly Monitor Wells

PCGCD 2014 Monthly Monitor Wells

PCGCD 2015 Monthly Monitor Wells

PCGCD 2016 Monthly Monitor Wells

PCGCD 2017 Monthly Monitor Wells

Monitor Wells Since 2011

Recharge

Pages 7-9 of the District Management Plan include information from the Texas Water Development Board pertaining to recharge.

Total recharge from precipitation for the Carrizo-Wilcox is 38,005 acre-feet per year.

Total discharge from the aquifer to the surface (springs, lakes, river, etc.) is 29,888 acre-feet per year.

Total flow into the District via the subsurface: 5,655 acre-feet per year.

Total flow out of the District via the subsurface: 3,123 acre-feet per year.

Net hydrologic gain (not accounting for pumping): 10,649 acre-feet per year.

 

Additional links:

The Water Cycle: Infiltration

Aquifer recharge: Functions and Uses

Underground Injection Control; AR & ASR

Enhancing Groundwater Recharge

Rainwater Harvesting: Soil Storage and Infiltration

USGS Drought and Groundwater