The Lake Pontchartrain Basin Foundation (LPBF) will produce Hydrocoast maps for six (6) time periods between May 2016 and March 2017 for the Barataria Basin. Each time period will have a salinity, biology and weather monitoring component assessing basin conditions. You can also view the Barataria Basin archived maps.
Barataria Basin Hydrocoast Map Series Summary
The first Hydrocoast map series for Barataria Basin was completed representing conditions for the week of May 23 through May 29, 2016. LPBF will be releasing future Hydrocoast maps for Barataria basin bi-monthly, with survey weeks on the following schedule:
July 18-24, September 12-18, November 7-13, January 2-8 and March 6-12
The Hydrocoast maps for the week of March 6 through March 12, 2017 for the Barataria Basin were produced using field data, MODIS, satellite imagery, precipitation data, wind data and permanent monitoring stations in the basin (USGS buoys, etc.). During this Hydrocoast period the salinity increased across the basin. The 0.5 ppt line also moved further inland to the interior of Lake Salvador. Discharge decreased at all river outlets and structures, except Bayou Lafourche where an increase was observed. Average daily discharge at outlets entering the basin was:
- Naomi Diversion Canal = 0 - 0 cfs
- West Pointe a la Hache Siphon = 0 to 0 cfs
- Bayou Lafourche, Donaldsonville = 374 to 399 cfs
- Bayou Lafourche, SW Donaldsonville = 452 to 451 cfs
- Bayou Lafourche, Thibodaux = 524 to 433 cfs
- GIWW, West of Bayou Lafourche = N/A cfs
- Davis Pond Diversion = 4,707 to 2,551 cfs
- Grand and Tiger Pass = 41,896 to 34,305 cfs
- West Bay = 25,120 to 20,787 cfs
- Southwest Pass = 169,515 to 142,161 cfs
The first map shows the salinity contours and freshwater discharge across the Barataria Basin. The solid line salinity contours are at 1 ppt salinity increments. The salinity is highest out past the Barrier Islands and decreases to fresh conditions (dark blue lines) in the basin. Sea water generally has a salinity of 32 ppt, but here the river has a significant influence of nearby gulf water. Green asterisks represent salinity leak points in barriers, usually in the form of gates in storm surge protection features but also in passes, portions of roads that are raised, canals, and bayous that are holes in the salinity barriers (pink lines). Salinity barriers are in the form of levees, roads, natural ridges and canals (with associated spoil banks). Salinity contours that are close together represent an area where salinity changes quickly over a short distance. Contours that are farther apart represent a more gradual change over longer distances.
The second map, the “Weather Map” shows the salinity contours in conjunction with weekly rainfall and wind roses in the Barataria Basin. During this Hydrocoast period there was rain across the basin ranging from 0.25 to 4 inches. Resultant winds were mostly from the north and northeast. Wind speeds ranged from 2 to greater than 11.1 m/s (2 to 25 miles/hr).
The third “Biological Map” shows oyster harvest area closure, as determined by the Louisiana Department of Health and Hospitals and the location of the public oyster seed grounds. Oyster area 8 was closed during this Hydrocoast Period, around the Bird’s Foot Delta. The biological map also shows the impaired water bodies for fishing and oyster propagation in the basin as prepared by the Louisiana Department of Environmental Quality under the EPA 305(b)/303(d) guidelines. Impairments due to metal contamination, residual effects from the BP oil spill and fecal coliform are shown.