Report on the lake

by CanuckBob Sun Nov 28, 2010 7:04 pm

I found this interesting report on the lake from another forum. Makes a good read.

Our Lake Chapala is Better than Ever

For 6 years the lake surface has been rather constant in the range of about
110,000 to 112,000 hectares while the lake volume has varied from about 62% to
82% full. It began to shrink about 1992 and reached a low in 2002 (about 20%
full) and did not start up again until 2003/04.

Lake level since 1980 has been more dependent on politics than rainfall. The 220
dams up the Lerma River could cut the lake to zero if they were not countered by
the political clout of Guadalajara. That is precisely why we NEED to not
encourage the less well informed to oppose the added pipeline to Guadalajara.
The current pipe takes about 8-10" off the lake each year. The proposed one may
take another 3" off the lake each year. The day Guadalajara finds another source
of water we all can assume the lake could be gone in a decade or so. The reason,
apparently not so obvious to the ill-informed protesters, is that the farmers up
the river will have no one to bend their arm to open the flood gates. These past
6 years of a near constant lake area attest to the fact that decades of
negotiation over the lake level have finally borne fruit.

The political clout of lakeside is near nothing compared to that of Mexico's #2
city. Please understand also that the lake has not seen water flow out to the
Santiago River for near 30 years and I expect it never will in the coming 100
years if ever. At a sediment fill rate of about 3 mm/year (1" in 8 years) we
should expect this lake like nearly all others in the world to become a
swamp/wetland and then a savanna in say 3000 years. We can delay this some by
creating wetlands where heavy runoff enters the lake. In turn such wetlands in
front of each wast water plant will assure an even cleaner lake. In the
meantime our lake can be a glorious place for all once more people shed the
indefensible words "dirty & polluted." Believe the past 3 years of coliform
tests which deem it quite low in bacteria, about 1/4 the limit for swimming,
clearly its water is cleaner than the average California beach which shows only
a cleaner appearing beach. Expect more good news as testing of the lake
continues. If we will clean up the trash at the lake edge we will have the
clean look as well as the clean water.

Note that evaporation takes 40" off the lake each year. The combination of
evaporation and pumping means the lake falls from a max about 01 Oct by about
53" to a minimum by 01 Jun.each year. Boats, docks, marinas, beaches and fish
habitats cannot be created to accommodate that kind of annual change.

Please, if anyone knows of any real data since 2000 that is contrary to the lake
described above I would love to know of it so I can adjust my view and help
encourage actions to remove whatever it may be that is not good.

Todd Stong