Chilika Lake (India) — New Sea Mouth and Salinity Restoration of a Ramsar Lagoon

Chilika is a roughly 906–1,165 km² brackish lagoon on India's Odisha coast and a Ramsar site supporting more than 200,000 fishers. By the 1990s littoral drift had choked the sea inlet, salinity fell, invasive freshwater weeds spread, fisheries collapsed (about 1,600 t/yr of fish and prawns) and the lake was placed on the Ramsar Montreux Record in 1993.
The Chilika Development Authority (created 1991/92) commissioned hydraulic modelling (CWPRS), which recommended a new mouth closer to the lake. A new inlet was opened on 23 September 2000, shortening the outflow channel by 18 km, with desilting of lead channels (IIT Madras reports a cost of about Rs 10 crore and roughly six months of works). A participatory micro-watershed programme in the basin aimed to cut silt load, and shrimp farming was banned.
Reported results (largely from the Authority's own head, so partly self-reported): fish and prawn landings rose from ~1,600 t/yr in the 1990s to a peak of ~14,000 t in 2004 (14,228 t in 2012); family income up about US$1,040 a year; water hyacinth and ferns (21.34 km² in Oct 2000) almost vanished; seagrass grew from 24.8 km² to 152 km² (2018); Irrawaddy dolphins rose from 70 (2003) to 145 (2013). The site left the Montreux Record in 2002. Sources differ on the fish multiple (7-fold vs 8-fold) and the dolphin claims come from institutional material.
Caveats: the intervention depends on keeping the new mouth open and on continued basin siltation control; independent peer-reviewed verification of all headline numbers was not located, and the mouth is hydraulic engineering rather than a payment scheme, so this is a nature-based restoration case rather than PES in the narrow sense.

Read the full analysis: https://ilec.or.jp/ILBMTrainingMaterials/wp-content/uploads/Ajit-Pattnaik_Lake-Chilika-Restoration_Report_2020.03.05.pdf