Integrated Assessment of Lake Degradation and Revitalization Pathways: A Case Study of Phewa Lake, Nepal

Avimanyu Lal Singh (), Bharat Raj Pahari and Narendra Man Shakya
Additional contact information
Avimanyu Lal Singh: Department of Civil Engineering, IOE, Pulchowk Campus, Tribhuvan University, Lalitpur 44700, Nepal
Bharat Raj Pahari: Department of Civil Engineering, IOE, Pulchowk Campus, Tribhuvan University, Lalitpur 44700, Nepal
Narendra Man Shakya: Department of Civil Engineering, IOE, Pulchowk Campus, Tribhuvan University, Lalitpur 44700, Nepal

Sustainability, 2025, vol. 17, issue 14, 1-23

Abstract: Phewa Lake, Nepal’s second-largest natural lake, is under increasing ecological stress due to sedimentation, shoreline encroachment, and water quality decline driven by rapid urban growth, fragile mountainous catchments, and changing climate patterns. This study employs an integrated approach combining sediment yield estimation from its catchment using RUSLE, shoreline encroachment analysis via satellite imagery and historical records, and identification of pollution sources and socio-economic factors through field surveys and community consultations. The results show that steep, sparsely vegetated slopes are the primary sediment sources, with Harpan Khola (a tributary of Phewa Lake) contributing over 80% of the estimated 339,118 tons of annual sediment inflow. From 1962 to 2024, the lake has lost approximately 5.62 sq. km of surface area, primarily due to a combination of sediment deposition and human encroachment. Pollution from untreated sewage, urban runoff, and invasive aquatic weeds further degrades water quality and threatens biodiversity. Based on the findings, this study proposes a way forward to mitigate sedimentation, encroachment, and pollution, along with a sustainable revitalization plan. The approach of this study, along with the proposed sustainability measures, can be replicated in other lake systems within Nepal and in similar watersheds elsewhere.

Keywords: hydrologic modeling; RUSLE; soil erosion; sediment control; watershed management (search for similar items in EconPapers)
JEL-codes: O13 Q Q0 Q2 Q3 Q5 Q56 (search for similar items in EconPapers)
Date: 2025
References: Add references at CitEc
Citations:

Downloads: (external link)
https://www.mdpi.com/2071-1050/17/14/6572/pdf (application/pdf)
https://www.mdpi.com/2071-1050/17/14/6572/ (text/html)

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:gam:jsusta:v:17:y:2025:i:14:p:6572-:d:1704697

Access Statistics for this article

Sustainability is currently edited by Ms. Alexandra Wu

More articles in Sustainability from MDPI
Bibliographic data for series maintained by MDPI Indexing Manager ().