Watersheds - Ugum and Piti Watershed Presentation

Watershed Management: Ugum & Piti-Asan Watersheds Shahram Khosrowpanah Funded by NOAA through Bureau of Statistics and Plans Guam Coastal Management Program (GCMP)

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June 25 04

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Aug 31 04

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Aug 31 04

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Watershed Protection Action ยง ยง ยง

Guam Coastal Nonpoint Pollution Control Section 6217-1990 Requires: Development of a multi-year Watershed Restoration Strategies Watershed assessment and identification of opportunities to reduce nonpoint source pollution for all Guam Watersheds WERI

Environmental Assessment for Non-Point Sources of Pollution for Ugum Watershed

Ugum Watershed Boundary

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Project Goals s

To assess the existing Natural Resources and identify areas within Ugum Watershed that have highest Potential to Contribute Pollution to the Streams and Coastal Areas

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How We Did It? ยง

Gather Physical and Environmental Data of the Ugum Watershed

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Develop a GIS Watershed Management Database

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Site Visitation to Areas with Highest Potential to Generate Pollution (with helicopter)

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Ugum – Digital Elevation Model (DEM)

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Vegetation Layer

Vegetation Distribution VEGETATIO N TYPE

Ravine Forest Savanna Grassland Agriculture Wetland Badland

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COVERAGE AREA (acre)

% OF THE TOTAL WATERSHED AREA

1859 2336

43 54

33 6 96

0.76 0.14 2

Soil Types Layer

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Land Ownership

75% 1.2% used

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Wetlands within Ugum Watershed

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Jeep Trails within the Ugum Watershed

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Site Visitation My Helicopter Crew

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Start of the Journey

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Talofofo & Ugum River joining together

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Farming along Ugum River

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Talofofo Fall

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Bank Erosion

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Bubulao & Ugum River joining together

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Bad Lands & Jeep Trails

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Land Sliding Upper Ugum River

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Watershed Protection Problems

Natural occurrence § Badlands § Bank erosion § Earthquake

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Human activities § Off-Road activities § Farming § Fire

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Developing a GIS-based Soil Erosion Model for southern Guam Watershed Dr. Shahram Khosrowpanah Mike Park Dr. Leroy Heitz Dr. Yuming Wen WERI

OBJECTIVES §

Developed a model that: a) estimates the upland erosion, and b) identifies areas of high soil erosion potential within a watershed.

– Universal Soil Loss Equation (USLE) – Geographic Information System (GIS)

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R factor K factor LS factor C factor P factor

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For each Grid Cell: A=RxKxLxSxCxP

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Recommendations s s s s

The Model may be used to simulate all possible scenarios for reducing soil erosion.

Land cover (C-factor) needs to be updated for Guam plants.

The management plan may implement certain vegetation types such as Vetiver Grass.

The public should be informed of the impact of off-road activities and programs to reduce the impacts should be in place.

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Developing a Watershed Management Plan for the Piti-Asan Watershed Dr. Shahram Khosrowpanah Dr. Mark Lander Sydonia Manibusan

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Piti-Asan Watershed

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Natural Erosion Contribution

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Problems associated with construction

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Project Goals ยง

To investigate the dynamic behavior of the Piti-Asan Watershed under different scenarios.

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To identify areas within the Piti-Asan watershed that contribute pollution to the streams and coastal areas.

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To develop management strategies that will prevent damage to the watershed.

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Data Collection

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Piti-Asan High Sediment Contribution Areas

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Potential Soil Loss within 100m Buffer (tons/acre/year) Site Description

Piti

% Change

Asan

% Change

Existing Condition

4.57

0

5.93

0

Hanjin Development

4.57

0

5.93

0

JHP Development

4.57

0

5.89

-0.67

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Recommendations v

Enforcement of erosion control practices during construction

v

The management plan may implement certain vegetation types such as Vetiver Grass, Hydroseeding

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Continuation of stream level and flow data collection

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Slope Stabilization, Silt fencing, Erosion socks, Check Dams

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Silt fencing

Erosion socks

Check dams Existing weir at Masso River

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WERI TECHNICAL REPORTS www.weriguam.org

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What Is Vetiver Grass Seedlings

Vetiver grass in Nature

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Comparison between Common Savanna Sword Grass and Vetiver grass Root systems Local Sword Grass

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Vetiver Grass