Nueces River & Groundwater Monitoring Update — September 30, 2025

Overview

Daily monitoring continued along the Nueces River and surrounding well field areas on September 30, 2025, documenting water quality, river stage, and site activity. Field readings collected using a YSI Pro30 Water Quality Meter were compared with U.S. Geological Survey (USGS) continuous data from the Bluntzer monitoring station (USGS-08211200).

Observations for the day reflect generally stable salinity and total dissolved solids (TDS) levels throughout the reach, with the well cluster continuing intermittent discharge and maintenance activity observed at Well 1.

Field Measurements — September 30, 2025

Instrument Used: YSI Pro30 Water Quality Meter

Well Field Update:

• Well 1: Maintenance crew observed on-site performing rework.

• Well 4: Not flowing during observation.

• Well Cluster: Continued operation noted with discharge flow visible.

Upstream Reading (86.5°F)

Freshwater conditions above the well field. Salinity measured at 0.6 ppt, TDS 765 mg/L.

Well Cluster Discharge (80.3°F)

Brackish flow at the discharge site with 3.0 ppt salinity and 3,603 mg/L TDS, consistent with cluster activity.

Hazel Bazemore Boat Ramp (82.0°F)

Slightly brackish conditions downstream. Salinity 0.9 ppt, TDS 1,163 mg/L.

USGS Data Summary — Nueces River at Bluntzer (USGS-08211200)

Time of reading: 2:00 PM CDT

• Gage Height: 6.66 ft

• Discharge: 41.3 cubic feet per second (cfs)

• Dissolved Oxygen: 8.5 mg/L

• pH: 8.4

• TDS (approx.): 877.5 mg/L

• Temperature: 82.0°F

Source: U.S. Geological Survey Continuous Monitoring, Nueces River at Bluntzer, TX

The data show that water levels have remained stable following a gradual decline from earlier peaks observed in late September. Dissolved oxygen levels remain healthy, indicating adequate aeration and flow through the reach.

Trend Observations

• Salinity and TDS: Values remain within typical ranges for the end of the dry season, with consistent gradients between upstream freshwater inputs and downstream brackish zones.

• River Flow: Slight reduction in gage height compared to September 29, consistent with receding river flow after last week’s minor increases.

• Conductivity: USGS specific conductance averaged 1,350 µS/cm @25°C, signaling minimal change in dissolved mineral content since the previous day.

Regional Hydrology Note

The Nueces River Basin continues to display conditions typical of a late-summer transition, where sustained heat and low rainfall influence both river and groundwater dynamics. Continued field monitoring helps document these shifts and ensure public access to current water quality and hydrologic data.

The Nueces Groundwater Conservation District (NGCD) remains focused on collecting and sharing reliable data to promote responsible groundwater management, transparency, and long-term conservation across Nueces County and surrounding regions.