Lake Atitlan: A Tarnished Beauty
CEO of Blue Water Satellite wants to help monitor problem with satellite imaging
By Greg Szymanski, JD
Aug. 13, 2010
The fresh water on our planet is in serious danger as more lakes and reservoirs are being taken over by toxic cyanobacteria, leaving the water undrinkable and dangerous to human health.
Save Lake Atitlan Mission, a Colorado non profit group, has tried to raise awareness of this serious problem, first using Lake Atitlan in the Guatemalen Highlands as a prime example.
The first step is to place an effective monitoring system into place because before you can solve a problem, the problem must be accurately identified.
Milt Baker, CEO of Blue Water Satellite in Ohio, a satellite imaging company specializing in detecting deadly cyanobacteria, has taken an interest in Lake Lake Atitlan.
Here are two blogs recently posted by Baker, emphasizing the seriousness of the problem at Lake Atitlan and how out dated and traditional hand grab sampling for cyanobacteria just doesn’t cut it anymore.
Lake Atitlan: a tarnished beauty
Lake Atitlan in Guatemala was once called the most beautiful lake in the world. Surrounded by three volcanoes this 30,000 acre lake and its beauty have been enjoyed by millions. It is also home to many descendants of the Mayan people. In recent years Lake Atitlan has become infested with Cyanobacteria tarnishing its once pristine beauty.
Cyanobacteria produce toxins which are extremely hazardous to health such as hepatotoxins which attack the liver and neurotoxins which attack the nervous system (See my blog Cyanobacteria: what you don’t know can hurt you). In addition to the potential for serious illnesses Lake Atitlan is sometimes malodorous and can produce skin rashes for anyone coming in contact with the water.
It is little wonder that tourism to Lake Atitlan has diminished recently .
Cyanobacteria like warm temperatures, food, and sunlight. Lake Atitlan is a case where through lack of environmental awareness raw sewage is dumped into the lake. That combined with Phosphorus run off from farm fertilizer has combined to stimulate the growth of Cyanobacteria.
Our company Blue Water Satellite uses satellite imaging to detect Cyanobacteria at parts per billion (ppb) levels. We are able to detect Cyanobacteria when it is still early in the bloom cycle so effective treatment methods can be used to kill it early before it becomes a significant bloom.
Blue Water Satellite is joining with a number of volunteer organizations to help clean up the lake. Blue Water will contribute satellite scans for no profit to organizations charged with clean up. With our help Lake Atitlan clean up efforts can monitor the effectiveness of treatment strategies.
There are a number of accepted treatment methods for clean up of lakes like Lake Atitlan. A few of them are listed below:
- Use Alum or an equivalent chemical to precipitate out the Phosphorus. This causes the food for the algae to sink to the bottom where the Cyanobacteria cannot use it, and the Cyanobacteria starves.
- Prevent Phosphorus from getting into the water. The most effective ways are to lessen the amount of Phosphorus that farmers use on their fields and to build Phosphorus remediation berms. Other techniques include the use of non-Phosphorus containing fertilizers like Biochar. Blue Water Satellite can detect Phosphorus on land and help farmers to lower applications.
- Build a sewage treatment plant to keep sewage out of the lake.
- Use water circulation machines. Several manufacturers of water circulation machines have shown effectiveness in controlling Cyanobacteria with machines that circulate the water. The theory is that the circulation may disrupt the photosynthetic process of Cyanobacteria and cause them to die. Typically these are only good for 30-50 acres requiring a large number for a lake the size of Atitlan.
Blue Water Satellite is joining the groups helping to save Lake Atitlan. If a lake as large and complex as Lake Atitlan can be cleaned up it is truly a prototype for efforts that will go on around the world to improve our environment.
Water quality measurement: small sample size may produce large errors
Today water quality monitoring is typically done by taking samples of lakes, rivers, streams, etc., and sending them to a laboratory for analysis. This technique is typically called “grab sampling”. Grab sampling is done to detect various pollutants such as Phosphorus, E Coli, and algae just to name a few. Grab sampling can produce large measurement errors.
Because of the expense of grab sampling, typically water bodies rely on just a few samples to measure water body quality and this small sample size can produce large errors. Grab sampling is a very labor intensive process requiring travel to a site, often the use of a boat and many man-hours of labor. Because of the labor intensity and cost, water bodies are frequently monitored with very few samples. For example one large lake I am familiar with is monitored with 5 samples for a 10,000 acre lake.
From the few data points available water body managers frequently draw inferences and are forced to make assumptions. Our company, Blue Water Satellite, uses satellite imaging technology to sample entire water bodies. We are able to measure 5 samples per acre so for a 10,000 acre water body we would make 50,000 measurements as compared with the 5 noted above.
Comparing our data with the grab sampling data we have seen many errors made because of the small sample size. Here are a few of the errors we have seen based on small sample size:
- One error we see is the assumption that the whole lake is represented by the few sample points. We have found significant variability in water bodies and a few data points cannot produce a statistically significant picture of the entire water body. Variability in the water body may be due to wind, current, springs, etc.
- Another error we see is it is assumed that concentrations of pollutants cannot change by very much over short distances. Again, although it is assumed that water is homogeneous, often point sources of pollution can impact particular areas of water bodies. We have seen cases where leaky septic fields or run off produce particular patterns in one part of a lake.
- A third error we see is assuming that pollution found in one area of the lake is a significant portion of the problem when it may be small when compared with other areas.
- A fourth error is that the statistical significance can be increased by taking a few samples and inputting them into a model. This may produce errors because the model makes assumptions about the water body that may or may not apply. For example some modeling takes land use type into account to predict Phosphorus run off. These models may or may not represent actual conditions.
Underlying all these errors is the fact that the state of the water body is not completely understood. This lack of understanding could lead to errors in remediation methodologies that may be costly and fail to produce results. For example installing an expensive aeration system may not be appropriate when lake wide data is reviewed.
From our experience the old carpenter’s rule of “measure twice cut once” has an analog in water quality monitoring; “measure more before deploying remediation strategies”.