The FlashPlayer app gives data for both NLA and NELP lakes. The database for the NLA lakes can be found here: https://iaspub.epa.gov/apex/aed_wmd/f?p=113:49::::::#content
But I cannot find the original database for the NELP lakes. I was able to download at least some of the data through the FlashPlayer app's export function, but I don't think I got it all.

In short, the design_info.csv, water_quality.csv, and sparrow_loads.csv should have complete data for NLA lakes. 
The water_quality_nelp.csv has data roughly analogous to the NLA data in water_quality.csv, but it may be incomplete and I could not find analogous data for the other two files.