MINIMUM FLOWS AND MINIMUM WATER LEVELS RE-EVALUATION FOR THE LOWER SANTA FE AND ICHETUCKNEE RIVERS AND PRIORITY SPRINGS PEER REVIEW RESOLUTION DOCUMENT FINAL DECEMBER 2020 Prepared for: Suwannee River Water Management District 9225 County Road 49 Live Oak, Florida 32060 Prepared by: 15711 Mapledale Blvd, Suite B Tampa, Florida 33624 ADA Statement Americans with Disabilities Act: The District does not discriminate upon the basis of any individual’s disability status. This nondiscrimination policy involves every aspect of the District’s functions including one’s access to, participation, employment, or treatment in its programs or activities. Anyone requiring reasonable accommodation as provided for in the Americans with Disabilities Act should contact the District at 386.362.1001 or 800.226.1066 (Florida only). The District’s fax number is 386.362.1056. Peer Review and Public Resolution Document CONTENTS Executive Summary ....................................................................................................................................... 1 Introduction .................................................................................................................................................. 4 Background ............................................................................................................................................... 4 Purpose ..................................................................................................................................................... 5 Response Summary ................................................................................................................................... 5 Section 1. Responses to Recommended Actions .......................................................................................... 8 Section 2. Specific Comments and Responses Table .................................................................................. 22 Attachment A. Infilling and Record Extension for USGS gage at US411. Attachment B. Environmental Flow Assessment Methods Attachment C. Event Approach Demonstration/Indicators of Hydrologic Alteration (IHA) i Peer Review and Public Resolution Document Executive Summary Chapter 373 F.S. and 62-40 F.A.C. provide the policy framework and authority for the Suwannee River Water Management District (District) and the Florida Department of Environmental Protection (FDEP) to set Minimum Flows and Minimum Water Levels (MFLs). Rule 62-42.300, F.A.C. (Minimum Flows and Levels and Recovery and Prevention Strategies) initially established MFLs for the Lower Santa Fe and Ichetucknee Rivers (LSFI) and associated priority springs in accordance with Section 373.042, F.S. Pursuant to Rule 62-42.300(1)(e), a re-evaluation of the MFLs was completed in December of 2019. The District initiated Peer Review of the Draft MFL Report titled “Minimum Flows and Minimum Water Levels Re-Evaluation for the Lower Santa Fe and Ichetucknee Rivers and Priority Springs” in December of 2019 (SRWMD, 2019). During the peer review process, the District also received comments from stakeholders. Both the Peer Review Panel (PRP) Report (Dunn, 2020) and the various stakeholder submissions are on file at the District. The primary purpose of this Resolution Document is to provide the District’s response to the PRP Report. The District will respond to stakeholder comments separately. A secondary purpose of this Resolution Document is to compare the fundamental differences between the technical evaluations reported in 2013 (SRWMD, 2013b) and 2019 (SRWMD, 2019) and to discuss these differences in the context of water management. The District has evaluated comments and used the best information available as directed by Florida Statute 373.042(1)(b). The District received many constructive comments, recommendations, and suggestions from the reviewers which, to the extent feasible and warranted, were incorporated into the final MFL Report. As required by Florida Statute 373.042(6)(b), significant consideration was given to the recommendations of the Final Peer Review Panel report in finalization of the MFL Report. The PRP Chair called for a complete MFL re-evaluation based on the magnitude-duration-return inter (MDR) Event Approach. Furthermore, assertions that the literature review should be updated to include a “state of science and practices” imply that the District team is somehow deficient in its knowledge of the various approaches that can be used to evaluated MFLs. The District respectfully disagrees on both items. The Chair’s Summary of the Panels’ Findings and Recommendations identifies other topics that are inferred in the re-evaluation MFL report but not explicitly discussed (e.g., Managing Uncertainty and Adaptive Management) or are not related to withdrawals (e.g., climate change). The District team agrees that these topics are important and exemplify challenges that stakeholders, and the District, will continue to consider when conducting water resource planning and water supply evaluations. Substantial responses to the PRP comments regarding those topics are provided herein. The MFL re-evaluation is a substantive demonstration of adaptive management in which the original MFL’s analysis was completed (SRWMD, 2013b) pursuant to the Florida Department of Administrative Hearings (DOAH) Findings of Fact and Conclusions of Law (DOAH, 2014) and then further expanded to: a) create a Reference Timeframe Flow (RTF) baseline record through Water Year (WY) 2015 using the North Florida Southeast Georgia Regional Groundwater (NFSWG) Flow Model to adjust 1 Peer Review and Public Resolution Document upward the historical flow records for groundwater withdrawal impacts on flow in contrast to the 2013 LSF MFL assessment for which a pre-1991 time period was used as the baseline flow record, b) utilize an expanded instream habitat evaluation using a more robust modeling software, the System for Environmental Flow Analysis (SEFA), and c) apply justifiable flow proportioning methods to evaluate MFLs for the Priority Springs and LSFR upstream of US441 that currently lack sufficient data for more quantitative assessment. The District asserts that the current Draft MFL Report should be appraised within these re-evaluation requirements and improvements. It was not the Districts’ objective to revisit methods that were deliberated in the previous review and hearing process, and resulted in the current MFLs Rule 62- 42.300, F.A.C. The District approach for its river system MFL evaluations has been two-pronged – 1) to use a cumulative frequency method for relatively high flows, developed by authors formerly with the SWFWMD (Munson & Delfino, 2007), and 2) to perform in-stream habitat modeling (e.g., SEFA), a method for low to moderately high flows that evaluates the change in in-stream suitable habitat area for various aquatic species and life stages. The District utilizes a top-down approach that requires identifying a baseline condition presumed to be unimpacted by withdrawals (i.e., RTF) from which some water is available for withdrawal. The District did not contemplate changing its approach for the re- evaluation of the LSFI MFL. Of key importance, is that the current District evaluation is consistent with and supported by the Event Approach and Indicators of Hydrologic Alteration (IHA) demonstrations described in this response document. The District is committed to developing scientifically based MFLs to prevent significant harm to the LSFI natural resources caused by withdrawals, and to ensure current and future water availability. The District acknowledges that differences of opinion may arise regarding various methods of analysis, which are not defined by the MFL statute. However, the cumulative frequency method and 15%-change criterion are the basis for far more MFLs adopted in the State of Florida than any other method, including the Event Approach promoted by the PRP Chair. The 15%-change criterion when applied to the change in frequency of higher flows and the change in viable instream habitat is a conservative approach that yields an allowable withdrawal of less than 8% from the median Reference Timeframe Flow (RTF) and not the historical flow. Literature documenting case studies of environmental flow assessments performed worldwide (Richter, Davis, Apse, & Konrad, 2011), associate the following tiers of protection of natural ecosystem structure and function, based on percent-of-flow reductions and risk tolerance of adverse environmental change, as a presumptive standard “… intended for application only where detailed scientific assessments of environmental flow needs cannot be undertaken in the near term.” • < 10% – high level of protection, low risk • 10-20% – moderate level of protection, moderate risk • 20% – low protection, high risk Using this standard applied to RTF values, the percent reductions associated with the proposed MFLs at high to median LSFI flows would be low risk and afford a high level of protection. During low-flow 2 Peer Review and Public Resolution Document conditions, the percent RTF reduction could temporarily exceed the 10% presumptive threshold; however, low flow WRVs are evaluated using in-stream habitat metrics. The 15% presumptive criterion is continually being vetted. It is widely used as a significant harm criterion in setting MFLs in Florida, and therefore is built into studies re-evaluating habitat condition, permitting, and recovery strategies – in other words, adaptive management. The realities and