This page presents my historical data on when the Main Vernal Pool first appears, fills, and when it dries up completely, along with depth at formation and maximum depth during its lifetime. Fairy shrimp reproduction was successful in all years except 2006, when most of the fairy shrimp died after the shallow initial pool dried up except for a few puddles. No new shrimp hatched when the pool refilled later that year.
The median date of filling is mid-February, but the pool has filled as early as October 20 and as late as February 28. The median depth at initial filling is 6 inches; in most years the pool eventually fills to its maximum depth of 16 inches. The median duration of the pool is four months, and varies from 2.5 to 8.5 months.
Rainfall Year Formation Date Disappearance Date Lifetime (days) Depth at Formation (inches) Max depth (inches) Successful fairy shrimp reproduction 1996-1997 12/10/1996 4/29/1997 140 8 16 yes 1997-1998 1/10/1998 7/14/1998 185 6 16 yes 1998-1999 no pool 1999-2000 2/21/2000 5/26/2000 95 6 14 yes 2000-2001 2/14/2001 5/31/2001 106 2 16 yes 2001-2002 no pool 2002-2003 2/13/2003 7/10/2003 147 6 16 yes 2003-2004 2/26/2004 5/10/2004 74 - 9 yes 2004-2005 10/20/2004 7/10/2005 263 1 16 yes 2005-2006 2/28/2006 6/15/2006 107 1 11 little 2006-2007 no pool 2007-2008 1/5/2008 ? ? 9 ? ?
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Copyright © 1996-2008 by Tom Chester.
Permission is freely granted to reproduce any or all of this page as long as credit is given to me at this source:
http://tchester.org/srp/vp/mp_filling_history.html
Comments and feedback: Tom Chester
Updated 14 January 2008.