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A Climatological History of Drought in the Apalachicola-Chattahoochee-Flint River Basin ... and an Update on an Eastern US Water War Paul Ruscher • email@example.com Science Division • Lane Community College Eugene, Oregon
First, the hook… Lake Jackson is a 4,000 acre lake in an enclosed 27,000 acre drainage basin north of Tallahassee, Florida. It suffers periodic drawdowns, emptying into three large sinkholes in an area of Karst topography. Image: Google Maps
September 16, 1999 Restoring a Disappearing Lake by GeorgannPenson, Northwest Florida Water Management District
The ACF Basin • 21st largest discharge of river systems in the US • Named most endangered river system in the US in 2016 (American Rivers) • Under interstate water disputes (in the courts) since 1990, when US Army Corps of Engineers decided to increase water allocations to Atlanta Metropolitan area (Lake Lanier) • Stevens and Ruscher (2014, J. Hydrol.)http://bit.ly/2mo1rvS
State Water Uses in the ACF • Primary Water Uses • Alabama • agriculture, industry, fisheries, recreation, preservation of habitats, power generation, navigation, water quality • Georgia • Potable water for metro Atlanta • Irrigation for agriculture • Unregulated withdrawls for center-pivot irrigation • Florida • 35% of freshwater to Apalachee Bay (oysters); ecology; navigation
Legal Disputes Complex Array of Uses • Zone 1 – navigation, water quality and supply, hydropower • Zone 2 – reduce navigation • Zone 3 – maintain water quality and supply; minimal hydropower; significant reduction for navigation • Zone 4 – significant reduction for hydropower; maintain for water quality & supply
Processed Climatological Data • PRISM dataset used to improve raw climatological records at NCDC – used Standardized Precipitation Index (SPI) • Primary stations analyzed for records from 1895-2005 • Sorted into primary climate divisions for 6 subregions • Impacts of main intra-annual climate drivers • ENSO • Pacific Decadal Oscillation • Atlantic MultidecadalOscil. • North Atlantic Oscillation • Long-term multi-year drought has major impact on water supply in the ACF, and these droughts were not typically considered as USACE modified water use plans
Canonical Correlation Analysis Methodology • CCA useful in multivariate analysis when predictors are correlated with each other • CCA helps to identify linear combinations of these predictors which have the maximum correlations with each other • Much prior research on drought in the southeast US has focused on the role of ENSO variability alone, but some newer studies suggested other factors • Climate change measures not incorporated directly into this study
Standardized Precipitation Index Albany, GA 1897-2005 Raw precipitation data are fitted to Gamma probability distribution and then normalized into SPI, and different averaging periods are used
Long-term Variability • Southern Oscillation Index (SOI) - + when La Niña, - when El Niño • Pacific Decadal Oscillation (PDO) - + when EPAC warm • North Atlantic Oscillation (NAO, dashed)– part of Arctic oscillation related to modulation of westerly winds, an atmospheric mode – others are ocean-atmosphere interactions • Atlantic Multidecadal Oscillation (AMO, not shown above) – related to SST
Establishment of strong subtropical ridge supports development of long-term droughts • CCA reveals dominance of NAO and AMO in drought determinations – when these are in phase and favorable for SE ridge – evident in max/min temperature series • CCA revealed long-term drought in 24-month SPI was dominated by NAO and PDO in the northern subbasins, and by SOI in the southern part (when T & precip are both used) • Water releases and decision-making are focused in the water supply and use in the northern basins, so ENSO/SOI should not be the driver in decision-making! • Top DJF; Bottom MAM
2nd Test: Role of SPI in revealing differences between northernmost and southernmost zones • Dominance of PDO and AMO in northernmost subbasin; varies according to SPI chosen (SPI 24 is best) • Florida subbasin dominated by SOI (ENSO) in MAM, JJA; SPI 3/6 show best results • This test – max/min T not utilized • Choices matter in data analysis methodolgies! • Top Upper Chat; Bottom Apalach
US Supreme Court Action 2013-2017 • Florida sued Georgia in 2013 (again), alleging Georgia is misusing its water allocation • JB Ruhl environmental lawyer advocating for ecosystem services approach in land use / water allocation law (former FSU law prof, now at Vanderbilt) filed amicus brief. See: • http://bit.ly/2m5kPNt • Case given to Special Master (Portland, ME) and ruling
Ecosystem Services and Equitable Apportionment • Ruhl: Evolutionary concept begun only about 20 years ago as ecologist, geographers, economists began working collaboratively to define how ecosystems function, and defining benefits (and costs). Cites several examples: • Oregon v. Idaho (1983) – apportionment of salmon in Snake River between two states • New Jersey v. New York (1931) – waste discharge in Delaware impacted by NYC waste – required minimum flows
Finding – No Valentine for Florida (2/14/2017) • USACE was not named as a party to the lawsuit • USACE allocates water • Special Master could not find he could compel a solution because USACE would be required to participate • Numerous lawsuits involving AL•GA•FL • $71 M in legal fees FL alone since 2001 Florida loses to Georgia in water wars ruling
Special Master Key Findings – Related to Drought • Historically, Apalachee Bay supplies 10% of national oysters, 90% of Florida supply • “There is little question that Florida has suffered harm from decreased flows in the (Apalachicola) River.” • Rejection of Georgia argument of Florida mismanagement of oyster beds • Low flows higher salinity invasion of oyster predators • Georgia substantially increased unregulated agricultural consumption of water since 1970 • Increased dependence on metro Atlanta water supply not in dispute • USACE considering new manual for controlling water distribution – which prioritizes Atlanta metro water supply – not originally considered in authorization for the dams on the ACF – motivation for next lawsuits? • http://www.miamiherald.com/news/local/environment/article132784134.html#storylink=cpy