Q: How much water does a standard fog collector gather?
A; It depends upon where you are located. One key issue is that you have to have fog. It will not collect water simply from humidity in the air. In some extremely foggy areas that have adequate wind, the standard fog collector can collect an average of somewhere between 1 and 10 liters per square meter per day. Since some days have no fog, this average means that on very productive days, a standard fog collector may collect as many as several dozen liters of water. The most I have managed to collect and measure in a 1-day period from one of my standard fog collectors is about 36 liters of water (over 9 gallons)!
Q: Does the mesh you use matter?
A: Yes. The amount of water collected by the mesh is a function of the properties of the mesh. The international standard mesh we use (a double layer of the 35% shade coefficient Raschel) works well, though there are other mesh that may also work well. The advantage of using the Raschel mesh is that it provides a standard that allows you to compare your results to those of others who use it in other places in the world. Recent research illustrates that different types of mesh perform better or worse than others, depending upon the characteristics of the fog event, such as how windy it is or how large the tiny fog droplets are.
Q: Can I build my own fog collector?
A: Certainly. We recommend that you start based on the recommendations and instructions that we provide for a standard fog collector.
Q: If I don't want to build my own fog collector, but I want one anyway, what should I do?
A: We can sell you an entire standard fog collector, or whatever parts of it that you can cannot build yourself. Prices for some of these parts are available on our site. Since some of the parts are rather bulky, shipping costs can be expensive, depending on where in the world you are located, which is why we encourage you to build what you can.
Q: Why is the frame made of copper tubing rather than something cheaper, such as PVC?
A: Frames made of PVC will tend to vibrate more in stronger winds and those vibrations will tend to "re-entrain" (that is, shake off) some of the water that was on the mesh. That would make direct comparisons between the standard fog collectors located at different sites problematic. This detail is decribed in the 1994 paper by Schemenauer and Cereceda.
Q: When I try to select shipping options, the system will not let me do it. What can I do to set up an order?
A: Please email us at email@example.com and we will generate a quote for you with the best shipping price to meet your needs. At the present time this is our best way to process orders and determine shipping costs.
Q: Is tax added to each order?
A: Tax is already included in the prices quoted.
Q: I am curious as to whether I can collect fog from near my house for some application, such as for watering my garden. What should I do?
A: Prior to investing in a large system, we recommend installation of a Standard Fog Collector, attached to a rain gauge with a data logger, for a year. This will measure very accurately the water that you can potentially collect per square meter of collecting surface. You would want to place the standard fog collector in an exposed area such that the mesh surface faces the prevailing winds that would be expected during most fog events.
Q: I set up some mesh overnight and it did not collect any water. What went wrong?
A: First of all, did you have any fog? If not, then the mesh will not collect anything. And even if you had fog, some fogs are less productive than others. To really see if you will collect water, you need to measure the amount it collects for an extended period of time. This image shows daily fog water totals from a standard fog collector deployed at CSUMB for a number of weeks during August 2017. Note the extensive periods of time without any water recorded. This is normal for many locations.
Q: How can I measure water collected from my standard fog collector?
A: You can certainly use a bucket or barrel to measure volume. However, that has several disadvantages.
1) You have to check it frequently and unless you take certain precautions, evaporation can occur during the days when there is no fog, reducing the amount you think you collected.
2) It is possible that the bucket can overflow, so if it is full when you get to it, you don't know how much water you might not have measured.
3) Your "time resolution" is only as good as how often you visit the site. So, if you are only interested in daily totals, you might be OK to check it once per day, at the same time, every day.
A more reliable method of recording measurements is to use a tipping bucket rain gauge with a data logger. The one I use costs a bit less than $100 for the rain gauge and a similar amount for the data logger
One logger I recommend is an Event Logger 101A by Madgetech. At $99, it will record only individual events, but can do so at a relatively fast sampling interval (e.g. 6-10 seconds, user controllable). Alternatively, other data loggers record the total number of tips recorded over a given time interval, say 15 minutes. I also like the Meter Environment/Decagon data loggers. I use the em50g, which utilizes a wireless cell-based technology. This allows you to check on remote sites via the Internet - how handy! It also allows you to connect up to 5 rain gauges simultaneously, though they need to be physically close to each other.
As far as rain gauges, I use most often the Rainwise which costs around $80-$100 depending on your source and on how many you order. This is the cheapest. I ask them to not send the LCD display, since that is not needed if you use a separate data logger. There are others that are of higher quality and greater cost, such as Meter Environment's ECRN-100, Campbell's, or others. Most can interface with any data or event logger, and I occasionally mix and match based upon what I have available. What is critical is to ensure that the rain gauge is calibrated so that you know what volume each 'tip' of the rain gauge represents.