The big problem is that since the erosion of the land barrier between the lower lake and ship channel, the lower lake is much more strongly coupled to the Gulf of Mexico and has much higher salinities. The two attachments show the salinity as measured at Hackberry and at Cameron. Since the erosion of the land barrier and increased coupling between the lower lake and lower ship channel, the salinity on the lake side of the weirs is closer to that at Cameron than at Hackberry.
If the coupling between the lower lake and ship channel could be reduced so that the lower lake had salinities closer to Hackberry, then the weirs could take greater advantage of fresh water infusions and be open more days per year without allowing too much salt to enter the marsh. Salinity levels below 8-10 parts per thousand (ppt) present much less risk to the marsh than levels above 15-20 ppt, which is where Cameron (and the lower lake) have spent most of the month of June.
|