Enhancing Ecosystem Services through sediment retention in Phewa

Lake of Western Nepal

Keshav Prasad Khanal and Sunil Kumar Regmi

Kathmandu

14 January 2015

Outline

• INTRODUCTION

• METHODS

• RESULTS AND DISCUSSION

• CONCLUSION

INTRODUCTION • Phewa Lake is second largest lake of the country

• Phewa Lake and its sub watersheds contributing different ecological services

• The Lake also contributes to the livelihoods in several ways

• The ES by the lake is valued at over US$43 million per year

• Sustainability of this benefit depends on the life of the lake

• Sedimentation is the major problem of the lake

• This paper aims to document the quantity of sediment loads coming from sub watersheds and explores possibilities for sediment retention in the upper catchments through establishment of Payment of Ecosystem Service (PES)

METHODS The methodology adopted for the study were:

1. desk review of wide range of secondary information

2. focused groups discussion

3. Consultations with stakeholders

4. mapping of Phewa sub-watershed with sediment transfer in Phewa lake; and

5. Scenario maps creation using InVEST software

RESULTS AND DISCUSSION Total area of watersheds: 11,351Ha. Present Capacity 42.18 million m3

Annual siltation rate (1990-1994): about 175,000-225,000 m3 If the lake is considered to be dead, when 80% of the storage is silted up and if the average sedimentation rate of about 180,000 cubic meters continues, the lake will be filled up with sediments in about 190 year from the year 1998 (Singh, 2013).

0

2

4

6

8

10

12

1950 1960 1970 1980 1990 2000 2010

Size of Phewa Lake is decreasing)

Capacity (Km2)

(JICA/SILT, 2002)

RESULTS AND DISCUSSION contd..

Major sources of sedimentation:

– Big landslides

– Rural road construction using bulldozer

– Traditional agricultural system

– Increased development activities

Soil loss intensity of the different sub watersheds

Sub-watersheds categorization based on Sediment transfer

• Category 1: Sarankot, Kaskikot, and Dhikur Pokhari VDCs

• Category 2: Eastern hill slope of Sarankot VDC, Pokhara Municipality (Ward No. 2, 4, 5, 6, 7 & 8)

• Category 3: Bhadaure Tamagi, Chapakot and Pumdi Bhumdi VDCs.

• immediate actions are required in category 1 – Major contributing factors: agricultural activities -

mono-cropping, cultivation in small terraces and heavy tillage

Conclusion • Sediments can be retained by

– improving farming practices • use of sediment laden diverting

runoff • in-situ manuring, • plantation of nitrogen fixing plants; • terrace riser slicing; and • use of compost and farm yard

manure (FYM) • terrace improvement; • Sloping Agriculture Land Technology

(SALT); • Some of the other recommended

activities for sediment retention are strip cropping; multiple cropping and high density planting and mulching.

– PES for sediment retention could be a feasible option

Recommended actions for PES

• Establish Phewa Lake Conservation and Management Interim Board with membership from the upstream communities and Phewa dependent stakeholders

• Establishment of Payers Association (fund collection and performance based payments) and Service Providers’ Association to ensure the continuous sediment retention service delivery

• MoU between the upstream communities and Phewa Lake beneficiaries

• Make provision for Third Party Monitoring and verification of the service provided

Key messages • Phewa Lake provides different Ecosystem Services and

the livelihoods for thousands of people around the Lake.

• The lake is decreasing in area and depth due to heavy sedimentation.

• Both the upstream communities and downstream Lake dependent communities could get mutual benefit from the PES; particularly sediment retention

• PES for sediment retention is feasible in Phewa watershed through establishment of independent Phewa Management Authority and other appropriate institutions for the effective delivery of sediment retention ES and payments against the performance of the services.

Acknowledgements

• Local communities of Phewa catchments and ,

• Hotel Association- Pokhara, Nepal Toursim Board, district government line agencies of Kaski district and other stakeholders provided information.

• Mr. Gokarna Jung Thapa of WWF Nepal- mapping the sub watershed based on sediment load contribution to Phewa lake and projecting the future scenario of sedimentation problem in the lake using InVEST tool.

This paper is made possible by the generous support of the American people through the United States Agency for International Development (USAID). The content is the responsibility of authors and does not necessarily reflect the views of USAID or the United States Government.