Article Hydrologic Restoration of the Lac des Allemands Swamp, Barataria, Louisiana Gary P. Shaffer 1, *, Demetra Kandalepas 1 , Nicholas Stevens 1 , Tessera Crockett 1 and Glen Curole 2   Citation: Shaffer, G.P.; Kandalepas, D.; Stevens, N.; Crockett, T.; Curole, G. Hydrologic Restoration of the Lac des Allemands Swamp, Barataria, Louisiana. Forests 2021, 12, 1074. https://doi.org/10.3390/f12081074 Academic Editors: William H. Conner and Thomas J. Dean Received: 26 June 2021 Accepted: 4 August 2021 Published: 12 August 2021 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). 1 Department of Biological Sciences, Southeastern Louisiana University, Hammond, LA 70422, USA; demetra.kandalepas@selu.edu (D.K.); nicholas.stevens@selu.edu (N.S.); tessera.crockett@selu.edu (T.C.) 2 Coastal Protection and Restoration Authority of Louisiana, 1440 Tiger Drive, Thibodaux, LA 70301, USA; glen.curole@la.gov * Correspondence: gary.shaffer@selu.edu Abstract: Most of the forested wetlands of coastal Louisiana are in decline, primarily due to impound- ment and increased flood duration. The Lac des Allemands swamp of Barataria Basin was a prime example of prolonged inundation prior to hydrologic restoration completed in February of 2018; the swamp had been impounded for over 60 years. To characterize restoration benefits, eight paired 625 m 2 permanent sites were established close to and halfway between eight 30 m × 122 m gaps cut into the spoil bank of Bayou Chevreuil. During 2018, canopy closure increased by 20%. In addition, aboveground production of wood and leaves increased over 2017 from 2018–2020. Furthermore, natural regeneration has occurred annually and many of the seedlings are now approximately 1 m tall. In conclusion, hydrologic restoration of impounded wetlands in coastal Louisiana is an extremely cost-effective landscape restoration method. Keywords: impoundment; hydrologic restoration; Taxodium distichum; swamp; natural regeneration 1. Introduction Most bald cypress–water tupelo (Taxodium distichum (L.) Rich, Nyssa aquatica (L.)) swamps in coastal Louisiana are degrading [1]. Stressors include saltwater intrusion, nutri- ent limitation, hydrologic alteration, herbivory, logging, and development. Many wetland restoration projects have been implemented or are being planned in coastal Louisiana. Sev- eral of these projects have been designed to alleviate flooding stress in bald cypress–water tupelo swamps [2,3]. One such effort was constructed in the Lac des Allemands swamp, located in the Barataria Basin of southeastern Louisiana. The restoration plan for this effort was written by the senior author of this manuscript in 2011. Shortly thereafter, the project was funded by the Coastal Wetland Planning, Protection, and Restoration Act at $7.88 million, but was constructed at under $500,000. On average, wetland restoration in coastal Louisiana costs about $70,000 per acre [3]; the cost for this project was $208 per acre, arguably the lowest cost of landscape restoration in Louisiana history. The wetlands of Barataria have been studied extensively for over 50 years [4]. In particular, the Lac des Allemands swamp has been studied since the mid-1970s [5]. Swamp aboveground production declined steadily over the next several decades [6,7] and exhibited little natural regeneration. Prior to restoration, this swamp was nearly permanently flooded, preventing seed germination and recruitment of bald cypress and water tupelo [5,8–13]. The hydrologic restoration in the 970 ha Lac des Allemands Swamp provided for pre- construction forested and herbaceous vegetation station establishment during fall of 2016. Monitoring the entire 2017 year provided data for computation of swamp productivity prior to project construction. Monitoring during 2018–2020 enabled us to begin measuring the response of the swamp to hydrologic restoration. The purpose of this study was to Forests 2021, 12, 1074. https://doi.org/10.3390/f12081074 https://www.mdpi.com/journal/forests