Rain puts the skids on drought pendulum
SFL Weekly Watersheds Summary: April 9 – 15

WEATHER. Last weeks rain came just when we needed it. It’s still too early to say what’s in store for the rest of April and May, but suffice it to say that last week’s drenching at least pushed the drought clock back a couple weeks in many necks of the woods. Most of the KOE watersheds historically average around 2 inches of rain in April. The rain showers that swept through this past week brought that and then some. Last week’s rain was heaviest in the southern part of the system. The lower east cost led the way with over 4 inches of rain. Big Cypress National Preserve receive around 2.5 inches. The Lake and Kissimmee Basins all received between 1-2 inches of rain in comparison. In terms of our dry season total, Big Cypress National Preserve has now received 9 inches in the 5.5 months that have elapsed since November 1st. Our long-term dry season average is 12 inches.

On a personal note, on the morning of the most intense rain storm, I observed through my front window that the morning paper had been dropped off, and was safely stowed in a plastic bag, so I felt no urgency to venture out in the rain to retreive it. But 20 minutes later when I saw the rain showing no signs of slowing I eventually did run out with an umbrella in hand to retrieve it. Shockingly the paper was gone. Exasperated, and at my whits end (and knowing no better), I followed the path of water flow. First it led me to the end of the driveway. Then 3 houses downstream. There the paper lay lodged and water drenched in a freshet of water at the gutter grate. Mystery solved! Granted it was a light mid-week edition (and possibly buoyied by an air pocket in the plastic bag), but I’ve never had a paper float away like that on me, even in the summer. (Of course most of our summer drenchings come in the later afternoon after I’ve already picked up the paper). Anyhow, it was a drenching no matter how you look at it.

BIG CYPRESS. Preserve-wide stage rose 1 foot from last week. That re-wound this year’s dry-season clock about 1 month: meaning that water levels are currently tracking at the same level now that they were a month ago in middle March. Historically speaking, preserve-wide stage is momentarily tracking right on top of our 5-year mid April average, and about 0.5 ft higher than middle April of last year. From the perspective of our wetland ecotones, preserve-wide stage has reflooded the very bottom of our swamp forest and marsh habitats. But keep in mind that there is a spatial component to this picture. Marshes and swamp forest habitat north of US41 remain dry, whereas wetland stage has risen into tall cypress and even shallowly into wet prairies south of US41 (particularly in the southeast corner of the preserve where it transitions into the Everglades).

EVERGLADES. Regulatory stage in 3A rose by a quarter of a foot, which rewound this year’s dry-season clock back just a few weeks to the same level it was in late March of this year. The rain soaked straight into the ground north of I75: water levels are still below slough land surface at Sites 62 and 63. Water levels in southern 3A are showing 1.3 ft water depths in comparison. Down in the Park, stage at its boundary with the Preserve in the marl prairie 5 miles south of US41 rose by a foot. This large increase is probably reflective of the water table having previously dropped below land surface. (The water table responds rises and drops more preciptiously when it drops below the surface into the underlying aquifer. In comparison, P33 in Shark River Slough rose by about a half foot, and is showing slough water depths of about 8 inches. Month after month for the past 7 months P33 had been setting new 5-year low-water marks, but now it has jumped up to the same level as the 5-year average for mid April, and even an inch or so above mid April of last year. Up in Loxahatchee, stage is tracking about a quarter of a foot below mid April of last year and the 5-year mid April average. Sloughs at Sites 1-7 and 1-9 are still holding about a half foot of water.

LAKE O. As of Sunday, Lake O stage stood at just around 10 ft msl. Current lake stage remains about 4 ft lower than mid April of last year, and about 4.3 ft below the mid-April 5-year average. Interior lake stage continues to track closely to the Spring 2001 drought year. That was the year that lake stage bottomed out at its historic low-water mark of 8.97 ft msl. Lake stage has now been below the bottom of the Lake’s interior-levee marsh (13.5 msl) for 12 continuous months, and its been close to 16 months since lake stage has fully inundated the full extent of the Lake’s interior-levee littoral zone (at >15.5 ft msl). It is worth noting that official computation of lake stage is not a simple endeavor, but involves utilization of multiple stations which are strategically placed throughout the lakes interior and at its edges (at structures). Official lake stage is based on 4 interior gages, but those readings are sometimes complemented with perimeter values in certain instances, such as when high-winds stir up the pot as has recently happened with the fronts moving through. Suffice it to say that the lake has a huge surface area (730 square miles) and 30 miles across the lake from north to south and from east to west (as the crow flies). It’s an incredible feat of technology, often overlooked and underappreciated, how comprehensively the intricacies of the lakes various components are monitored. Kudos to all involved!

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