Enhancement of the SWAT-REMM System for Simulation of T-N Reduction Efficiency with Riparian

Buffer System at Bonggok watershed

Enhancement of the SWAT-REMM System for Simulation of T-N Reduction Efficiency with Riparian Buffer System

at Bonggok watershed

2010 SWAT Conference Annual International Meeting

August 4-6, 2010

Jichul Ryu, J. P. Cho, I. J. Kim, Y. Mun, J.P. Moon, N. Kim, S.J. Kim, D.S. Kong, K.J. Lim Kangwon National Univ., South Korea

Introduction

BMPs, Riparian Buffer System, The purpose of this study

Introduction

Various Best Management Practices (BMPs) have been proposed to mitigate adverse impacts on water bodies and ecosystem of non-point source pollution.

The riparian buffer system (RBS) has been recommended among a lot of researchers studying in this field.

The SWAT-REMM prototype model was developed by the researchers in Canada.However, the SWAT-REMM prototype model has a lot of limitation.

The purposes of this study are to:I. Improve the prototype version of the SWAT-REMM system

II. Simulate water quality improvement with riparian buffer system using SWAT-REMM enhanced model

Methodologies

REMM, SWAT-REMM prototype, SWAT-REMM enhanced system

Wha

t is t

he R

EMM

mod

el ?

What is SW

AT-REMM

Prototype?Liu, Y., Yang, W., and Wang, X.(2007). GIS-based Integration of SWAT and REMM for

Estimating Water Quality Benefits of Riparian Buffer in Agricultural Watersheds. Transactions of the ASABE, 50(5), pp. 1549-1563.

Buffer Drainage

Concentrated Drainage

Limitations of SWAT-REMM Prototype

The SWAT-REMM prototype …• can NOT simulate riparian buffer system established at severalsubwatersheds

• can NOT reflect soil properties of riparian buffer zone at studywatershed

• can NOT consider multiple weather stations

• can NOT consider NO3-N load in baseflow through riparian buffersystem

•was NOT tightly coupled (run SWAT first, run REMM and then run SWAT routing manually)

Development of SWAT-REMM Enhanced system

Enhancement of SWAT-REMM system

SWAT Watershed Delineation Interface was modified to delineates buffer/concentrateddrainage for user-specifying reach segment

1. Can simulate riparian buffer system established at several subwatersheds.

Enhancement of SWAT-REMM system2. Reflects soil properties of riparian buffer zone at study watershed

Buffer Zone1

Buffer Zone2

Buffer Zone3

Subwatershed, Buffer zone

Soil LayerLayer 1

Layer 2

Layer 3

Sub. 1,Buffer 1

Sub. 2,Buffer 2

Sub. 3,Buffer 3This soil property in Canada watershed

were hard coded in SWAT-REMM prototype

SWAT-REMM PROTOTYPE users have to modify soil properties in riparian buffers with local soil data

manually

Enhancement of SWAT-REMM system2. Reflects soil properties of riparian buffer zone at study watershed

Enhancement of SWAT-REMM system2. Can reflects soil properties of riparian buffer zone at study watershed

Enhancement of SWAT-REMM system3. Can consider multiple weather stations in riparian buffer zones

Subwatershed 1

Subwatershed 2

Subwatershed 3

Subwatershed 4

SWAT-REMM Prototype SWAT-REMM Enhanced

Enhancement of SWAT-REMM system3. Can consider multiple weather stations in riparian buffer zones

SWAT-REMM Prototype SWAT-REMM Enhanced

One representative weather station

Multiple weather stations

Enhancement of SWAT-REMM system3. Can consider multiple weather stations in riparian buffer zones

SWAT-REMM PrototypeSWAT-REMM Enhanced system

Enhancement of SWAT-REMM system4. Can consider NO3-N load in baseflow flowing into riparian buffer system

Enhancement of SWAT-REMM system4. Can consider NO3-N load in baseflow flowing into riparian buffer system

Enhancement of SWAT-REMM system5. SWAT-REMM enhanced system is now tightly coupled

click

Application ofSWAT-REMM Enhanced system

Study area, scenarios of riparian buffer systems

Application of Study Watershed (South Korea)

Scenarios of Riparian Buffer system

Scenarios of Riparian Buffer system

Results

Calibration and Validation , Application of the SWAT-REMM enhanced system

Calibration and Validation of Stream Flow

Daily Calibrationin year 2005

Daily Validationin year 2006

Calibration and Validation of T-N

Daily Calibrationin year 2005

Daily Validationin year 2006

Estimated reduction with Riparian Buffer System (RBS) Scenarios

Stream flow

Subwatershed

BeforeRBS

(m3/sec)

Buffer 10m(Scenario 1)

Buffer 5m(Scenario 2)

Buffer 1m(Scenario 3)

After RBS(m3/sec)

Reduction(%)

After RBS(m3/sec)

Reduction(%)

After RBS(m3/sec)

Reduction(%)

10 8.7 8.3 4.7 8.4 4.3 8.6 2.1 11 3.5 2.8 18.7 3.0 14.5 3.2 6.9 12 7.8 6.0 23.1 6.3 18.5 7.0 10.2

T-N

Subwatershed

BeforeRBS

(kg/year)

Buffer 10m(Scenario 1)

Buffer 5m(Scenario 2)

Buffer 1m(Scenario 3)

After RBS(kg/year)

Reduction(%)

After RBS(kg/year)

Reduction(%)

After RBS(kg/year)

Reduction(%)

10 86.6 73.7 14.8 77.5 10.5 80.6 6.9 11 18.3 10.5 42.4 12.6 31.3 13.8 24.5 12 75.8 34.8 54.0 48.7 35.7 51.9 31.6

Conclusions4

» ...is available to simulate riparian buffer system established at several subwatersheds

» …reflects soil properties of riparian buffer zone at study watershed

» ...considers multiple weather stations in riparian buffer zones

» ...considers NO3-N load in baseflow flowing into riparian buffer system

» ... is now tightly coupled

Conclusions SWAT-REMM enhanced system ...

» SWAT-REMM enhanced system was improved.

» Reduction efficiency was affected by riparian buffer width.

» However, REMM model in SWAT-REMM system was not calibrated and validated in this study.

» Still, several items in the enhanced SWAT-REMM System have to be improved.

Conclusions

I really appreciate Liu, Y., Yang, W. and Wang, X for sharing the SWAT-REMM prototype source codes and modules.

Http://www. Envsys.co.kr/E-mail:swatremm@gmail.com