Fog Collection System - Water!

June 17, 2011 - Parque Nacional Volcán Nevado de Colima, México

It had been three weeks since I last visited our 1 meter square test size fog collection system in the park. During that time period it could be seen from the city that a change in the months long weather pattern was occurring. Light thunder storms were seen nearly each evening around the mountain area and briefly in the city itself. Accompanying the weather change was fog that totally obscured the city's view of the mountain top.

Until today the maximum collection from the system had been virtually negligible, perhaps 50-100 ml of water. Approaching the test system I could see a significant water level in the 20 liter storage tank; the tank was just shy of being half full of water, ~9.0 liters.

The open collection trough is able to receive direct falling rain not associated with the mesh capture system. To separate out the data on direct rainfall to the trough we use a rain gauge and the known trough dimensions. The rain gauge contained barely half an inch of collected water, which equates to accounting for about 1 1/3 liters. This indicates the mesh system directly captured approximately 7 2/3 liters of water.

Scaling the test data up to a full size system of 40 square meters, a single unit would have captured 360 liters of water. The fog collection system's mesh would account for capturing nearly 309 liters of that volume of water. This suggests a greater efficiency of land use with a fog collection system to that of the current rain catchment programs employed in the preserve.

The site has the potential to host a great number of full size units, however 2-5 units will likely be installed in this first phase. The full size units will differ greatly in comparison to the test size units in the design of their support system. Currently construction drawings are being developed and installation will follow promptly.

As part of this project we will be developing educational materials to be made available to park visitors in the environmental education center. The materials will describe construction methods for fog collection systems and considerations for locating. The fog collection test site itself is available for visitors to examine up close.

The test site is located on edge of a precipice that falls down several hundred feet of a lush green pine, fern, and mossy drop. The precipice forms a large gorge that remains somewhat green even at the height of the dry season. This is due to the ability of the vegetation to capture water from the fog onto the foliage. The gorge has an upward slope that seems to breath the fog up and down cyclically. The intensity and frequency of the fog does diminish greatly at the height of the dry season, but not entirely.

I am excited that this early data indicates fog collection systems may be a viable option for supplying additional water to the tree nursery and expanding the reforestation efforts.