The purpose of the trial is to examine the effect of a 95% shade cloth cover over a canal. Our goal is to determine if this level of light reduction is capable of lowering the numbers of blue green algae in the canal. Our hypothesis is that by reducing the number of algae cells in the canal, we may also reduce the production of MIB and geosmin. These compounds impart unpleasent taste and odors to drinking water.
Photo of shade screen
Close-up photo of shade screen
Photo of shade screen and canal
Date | Location | Time | pH | Temp (C) |
DO (mg/L) |
TDS (mg/L) |
Nitrate (mg/L) |
Ortho- Phosphate (mg/L) |
Total Phosphate (mg/L) |
||
May 7, 98 | Before Screen | 12:40 | NS | 22.5 | 8.9 | 560 | 0.19 | 0.08 | 0.66 | ||
May 7, 98 | End of Screen | 12:50 | NS | 22.4 | 9.0 | 560 | 0.19 | 0.10 | 0.68 | ||
April 22, 98 Initial |
Pre-screen middle of site |
12:00 | NS | NS | NS | NS | 0.21 | 0.04 | 0.57 |
Algae counts for April 22, 1998 |
Phytoplankton (cells/ml) |
Periphyton (cells/ml) |
Cyanophytes | ||
Aphanotheca | 4,333.33 | 241.18 |
Microcystis | 18,000 | 553.37 |
Spirulina | 666.367 | none recorded |
Lyngbya | none recorded | 62.22 |
Chlorophytes | ||
Ankistrodesmus | 1333.3 | none recorded |
Chlorella | 3333.33 | none recorded |
Scenedesmus | 4000 | none recorded |
Rhizoclonium | none recorded | 116.65 |
Schroederia | none recorded | 139.86 |
Ulothrix | none recorded | 209.79 |
Chrysophytes | ||
Amphipleura | 666.67 | none recorded |
Cocconeis | 2000 | 489.51 |
Cymbella | 2666.67 | 273.25 |
Fragilaria | 1333.33 | 318.65 |
Gomphonema | 666.67 | 88.35 |
Navicula | 3333.33 | 227.86 |
Diatoma | none recorded | 46.62 |
Synedra | 3333.33 | 167.49 |
Tabellaria | 666.67 | none recorded |
Gyrosigma | none recorded | 55.89 |
Melosira | none recorded | 122.73 |
Cyanophytes | ||
Aphanothece | 4333.33 | 241.18 |
Microcystis | 18,000 | 553.37 |
Spirulina | 666.367 | none recorded |
Lyngbya | none recorded | 62.22 |