Jeff J. Dauzat LDEQ Southeast Regional Office New Orleans, Louisiana (504) Bonnet Carre’ Spillway Opening

Louisiana Department of Environmental Quality (LDEQ) drafted and implemented a Sampling Plan to monitor water quality in Lake Pontchartrain as a result of the opening of the Bonnet Carre’ Spillway. The sampling plan was developed in conjunction with other Federal and State Agencies to avoid duplication of effort.

Site 0035 Pass Rigolets Site 0109 Chef Menteur Pass LDEQ Sampling Sites Site 0217 Causeway Crossing # 6 Site 0138 Causeway Crossing # 4 Site 0216 Causeway Crossing # 2 Bonnet Carre’ Spillway New Orleans Slidell

Pass Rigolets Site 0035

Chef Menteur Pass Site 0109

Causeway Cross-Overs Site 0217 Causeway Crossing # 6 Site 0138 Causeway Crossing # 4 Site 0216 Causeway Crossing # 2

Water Quality Parameters True Color Specific Conductance TDS TSS Chloride Sulfate Alkalinity Turbidity Sodium TP TOC COD BOD Hardness Ammonia-Nitrogen TKN Nitrate+Nitrite Nitrogen VOC’s

bromochloromethane chloromethane vinyl chloride bromomethane chloroethane trichloroflouromethane 1,1 –dichloroethene methylene chloride trans 1,2- dichloroethene 1,1 –dichloroethane chloroform 1,2 –dichloroethane 1,1,1 –trichloroethane carbon tetrachloride 1,2 –dichlroropropane trichloroethene bromodichlroromethane cis- 1,3 –dichlroropropene trans- 1,3- Water Quality Parameters – VOC’s dichloropropene 1,1,2 –trichloroethane 1 –chloro-2- bromopropane dibromochloromethane tetrachloroethene bromoform 1,1,2,2- tetrachloroethane flourobenzene methyl-t-butyl ether benzene a,a,a-trifluorotoluene toluene chlorobenzene ethylbenzene 1,3- dichlorobenzene 1,4-dichlorobenzene 1,2-dichlorobenzene

Time Date Sample depth (m) Temperature ( 0 C) Conductivity (umhos/cm) Salinity (ppt) pH ( SU) Dissolved Oxygen (mg/L) % Dissolved Oxygen Field Parameters

First sampling event on 04/11/2008: No remarkable significance – baseline to establish background Sample results Second sampling event on 05/02/2008: Changes in sample results between sample events show increases in nutrients and suspended solids. Changes in sample results between sample events show decreases in alkalinity, sulfate and conductivity.

Changes in field parameters were noted after the Bonnet Carre’ Spillway opened: % Dissolved Oxygen increased to super saturation levels – algae blooms. Conductivity reductions – fresh water. Salinity reductions – fresh water. pH elevation – algae blooms. Temperature fluctuations – fresh water. Zero Dissolved Oxygen reading at Site 0138 on 04/25/2008. WQ meter anomaly. Summary of Findings

Questions ?