DEVELOPMENT OF WATERSHED MANAGEMENT STRATEGIES BASED ON CALCULATED CARRYING CAPACITY

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DEVELOPMENT OF WATERSHED MANAGEMENT STRATEGIES
BASED ON CALCULATED CARRYING CAPACITY

• P.C. CHIANG1, T.F. LIN2, C.M. KAO3,
• Y.L. YAN4 E.E. CHANG5
• 1National Taiwan University  
• 2National Cheng Kung University
• 3National Sun Yat-Sen University
• 4Da-Yeh University
• 5Taipei Medical University

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Introduction

• Major watersheds in Taiwan are polluted.
  Appropriate river and watershed management
  strategies need to be established.
• Carrying capacity for each watershed needs to be
  determined
• to aid decision-maker in developing management
  strategies.
• Methodologies for assessing carrying capacity
  needs to be
• constructed.
• Kaoping watershed was selected as a case study
  site. Results and developed management strategies
  could be applied for other watersheds in Taiwan.

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Objectives

• Carrying capacity calculation for three media
  water, soil, and air.
• Case study - Kaoping watershed carrying capacity
  evaluation.
• Kaoping watershed management strategies
  determination.

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Evaluation of Kaoping River Carrying Capacity
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Background Information

• The Kaoping River basin is the largest and the
  most intensively used river basin in Taiwan. It
  is 171-km long, drains a catchment of more than
  3,250 km2.
• Kaoping River serves as a source of water supply
  to the Kaohsiung City, several towns, two
  counties, and a number of large industries
  (electronic, steel, petrochemical, etc.). It also
  receives their treated and untreated wastewater.
• Recent water quality analysis indicates that the
  Kaoping River is heavily polluted.
• Because of the poor raw water quality, the cost
  for water treatment has been significantly
  increased.

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Background Information

• The major water pollution sources in Kaoping
  River are livestock wastewater from hog farms,
  municipal wastewater, industrial wastewater,
  non-point source (NPS) pollutants from
  agricultural areas, and leachate from riverbank
  landfills.
• Less than 5 of sewer connection in the Kaoping
  River basin.
• Most of the municipal wastewater is discharged
  into the river
• without treatment.
• The hog population is estimated to be one million
  in the whole
• basin, and half of the population is in the
  lower catchment. The
• hog farm waste is one of the major causes of the
  deterioration of river water quality.

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Model Analysis

• Enhanced Stream Water Quality Model (QUAL2E) was
  selected as a water quality-planning tool to
  perform the water quality evaluation and carrying
  capacity calculation.
• The QUAL2E Windows interface was developed by
  U.S. EPA to assist the implementation of the
  Total Maximum Daily Load (TMDL) program. It can
  simulate up to 15 water quality constituents
  including BOD, nutrients, DO, temp, algae as
  chlorophyll A, and coliforms.
• Results demonstrate that the simulated data had a
  good match with the analytical water quality
  results.

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Investigation Results

• Based on the investigation, the current daily
  BOD, NH3-N, and TP loadings to Kaoping River are
  74,700, 39,400, and 5,100 kg, respectively. Daily
  E-Coli loading is 3.5E16 CFU.
• Results indicate that the hog farm wastes
  generated from one million hogs contribute 37,800
  kg BOD per day, which is more than half of the
  daily BOD loads to the river.
• The untreated municipal wastewater contributes
  more than 25 of the daily BOD loading.
• Significant effects of the riverbank landfills on
  water quality were also observed. The landfill
  leachate contributes 2,800 kg per day of the BOD
  loading (close to 4 of the daily loads) into the
  river.

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Carrying Capacity Results

• The carrying capacity calculations for BOD,
  NH3-N, TP, and E-Coli were performed using the
  calibrated QUAL2E water quality model to obtain
  the maximum acceptable BOD, NH3-N, TP, and E-Coli
  loadings per day without violating the water
  quality criteria for Kaoping River.
• The calculated BOD, NH3-N, and TP carrying
  capacities are 27,700, 4,200, and 600 kg per day.
  Daily E-Coli carrying capacity is 4.8E15 CFU.
  The current BOD, NH3-N, TP, and E-Coli loadings
  are almost 2.7, 9.4, 8.5, and 7.3 times higher
  than the calculated carrying capacities,
  respectively.
• To protect public health and improve the river
  water quality, the river management scenarios are
  proposed.

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Simulated BOD loading after the implementation
of each proposed plan
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Simulated NH3-N loading after the implementation
of each proposed plan
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Simulated TP loading after the implementation of
each proposed plan
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Simulated E-Coli loading after the
implementation of each proposed plan
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Strategies and Implementation

• The following measures are required to reduce the
  daily BOD, NH3-N, TP, and E-Coli loads
• 1. hog ban in the whole Kaoping River basin,
• 2. sewer system construction to achieve 30 of
  connection in the
• basin within 10 years,
• 3. removal of 10 riverbank landfills, and
• 4. enforcement of the industrial wastewater
  discharge standards.
• Approximately 48,000 kg of daily BOD loading can
  be reduced, and the remaining BOD loading (26,700
  mg/day) is lower than the 27,700 mg per day BOD
  carrying capacity. NH3-N, TP, and E-Coli loads
  are still far beyond the calculated carrying
  capacities.

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Conclusions and Recommendations

• The proposed comprehensive strategy for Kaoping
  River basin management consists of
• 1. short-term management and improvement
  measures (e.g., 10 riverbank landfills removal).
• 2. long-term structural measures (e.g., sewer
  system construction), and land use management
  and legislation (e.g., hog ban and enforcement
  of wastewater discharge standards).

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Conclusions and Recommendations

• Other water quality protection strategies
  include
• (1) Application of N and P treatment
  technologies.
• (2) Groundwater protection and groundwater
  quality monitoring.
• (3) Establishment of buffer strip and source
  water protection zone.
• (4) Establishment of total maximum daily loads.
• To provide high quality drinking water, two other
  issues have been addressed
• (1) establishment of appropriate river and raw
  water quality criteria for the Kaoping River,
  and
• (2) application of the advanced water treatment
  technology for raw water treatment.

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Evaluation of the SoilCarrying Capacity for
Kaoping Area
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Introduction

• Soil is a fundamental building block of the
  natural system.
• Excessive loading of pollutants should be
  prevented to maintain the long-term productivity
  and sustainability of soils.
• Pollutant loading that causes ceiling level
  (carrying capacity) should be defined

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Introduction

• Carrying capacity of soil is considered as that
  no adverse effect is posed to the people or to
  the ecological system from the soil.

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Objectives

• to develop a scheme to estimate the carrying
  capacity of pollutants for soil
• to determine the carrying capacity for Kaohsiung
  and PingTong Area (Kao-Pin Area)
• to propose strategies for the control of soil
  pollution

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Methods Soil Carrying Capacity
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Methods Transport Model

• SESOIL
• a one-dimensional vertical transport model
• can simulate long-term movement and distribution
  of pollutants in the unsaturated zone.
• covering most of the physical, chemical, and
  biological mechanisms for the pollutant/soil
  system.

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Methods Transport Model

• SESOIL
• hydrogeological simulation, soil deposition
  movement, and contaminant transport are accounted
  for.
• Five categories of input parameters, including
  meteorological data, soil properties, chemical
  characteristics, application data, and washload,
  are needed in the model.

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Methods Exposure Model

• Pathways considered
• ingestion of soil, drinking water, and vegetables
• inhalation of air and airborne dust
• dermal contact of contaminated soil
• USEPA models are used
• Local parameters are used if possible
• Or USEPA defaulted values are used

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Methods Carrying Capacity Calculation

• 2 organic compounds, benzene and tricholoethene,
  and 2 heavy metals, chromium and mercury, were
  selected as representative pollutants
• 4 different soils (Kao-A, Kao-B, Pin-A, and
  Pin-B) typically present in the Kao-Pin Area were
  chosen as representative soils.

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Methods Carrying Capacity Calculation

• Meteorological data in the Kaopin Area
• Based on the transport model, pollutant
  concentrations in the air, water, and soil at
  different time can be obtained for different
  scenarios of initial pollutant concentrations in
  the soil.

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Methods Carrying Capacity Calculation

• The exposures from different pathways to human
  and animals can be calculated.
• Human carcinogenic pollutants
• extra risk of 10-6
• Non-carcinogens
• hazard quotient 1

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Methods Carrying Capacity Calculation

• Ecological risks for the representative animals
• similar to that for the non-carcinogenic
  compounds.
• Carrying capacity
• determined at the soil levels with risks smaller
  than that for human health and ecology.

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Conclusions Carrying Capacity Calculation

• Groundwater Pollution Potential

Proposed Clean-up Standard Benzene 5 mg/kg,
TCE 60 mg/kg
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Conclusions Carrying Capacity Calculation
Human Health Risk
Proposed Clean-up Standard Benzene 5 mg/kg,
TCE 60 mg/kg
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Conclusions Carrying Capacity Calculation
Human Health Risk
Proposed Clean-up Standard Chromium 250 mg/kg,
Mercury 10 mg/kg
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Conclusions Carrying Capacity Calculation

• Ecological Risk

Proposed Clean-up Standard Chromium 250 mg/kg
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Conclusions Sustainable Soil Quality

• Sustainable indicators of soil quality
• potential for soil pollution
• total area of polluted soil
• total area of remediated sites

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Conclusions Sustainable Soil Quality

• Potential for soil pollution
• connection ratio of sewage,
• degree of industrial wastewater treatment,
• degree of industrial waste treatment,
• degree of air pollutant emission control,
• application rate of pesticides, and
• application of chemical fertilizers.

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Conclusions Sustainable Soil Quality

• Total area of polluted soil
• a database about the contaminated status of all
  the probable contaminated sites, including USTs,
  illegal dumping, landfills, and sick-hog landfill
  sites, should be established.
• Determination of the contaminated status of a
  site is suggested to be based on the three
  approaches for calculating carrying capacity.

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Conclusions Sustainable Soil Quality

• Total area of remediated site
• 90 of the contaminated agricultural fields are
  proposed to clean up by year 2011
• all the sites discovered by today should be
  remediated or in the process of remediation

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Conclusions Implementation

• Reduction of pollution potential
• Encouragement of site investigation
• Development of low-cost remediation-related
  technology
• Encouragement of site remediation

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Evaluation of the AirCarrying Capacity for
Kaoping Area
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Objectives

• Develop a simplified model that can be used to
  evaluate air carrying capacity
• Evaluate the air carrying capacity in Southern
  Taiwan area
• Evaluate possible strategies when Total emission
  control policy applied in each air Quality
  regions

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Methods Carrying Capacity Calculation

• Evaluate the air carrying capacity in Southern
  Taiwan area
• Emission source data from EPA were used to
  estimate the total loading by ISCST3 model at
  selected monitoring stations from the EPAs
  monitoring network. The total loading included
  point, line, and area sources from local emission
  sources or exterior sources by long range
  transport from near by area.

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Methods Carrying Capacity Calculation

• The Roll-back method was then used to calculate
  the total carrying capacity at the selected
  monitoring station.
• Finally, by comparing between the exist air
  quality and the ambient air standard, the excess
  carrying capacity were estimated to understand
  whether more pollutants can be emitted or some
  sources should be reduced to meet the air quality
  standard.

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PM10 Point Sources in Southern Taiwan Area
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PM10 Line Sources in Southern Taiwan Area
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PM10 Area Sources in Southern Taiwan Area
PM10 Point sources in Southern Taiwan area
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Results

• Total Six Monitoring Stations were simulated
• An-Nan station
• For year 1999, the results show that lowest net
  excess air carrying capacity occurs in November
  with a value of -3018 tons/year. For other months
  such as January, March, and December, the air
  pollution problems are all very serious, and the
  net excess air carrying capacities are all
  negative values for all these month.
• If calculated by annual average air quality, the
  net excess air carrying capacity is -391
  tons/year.

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Results

• Feng-Shan station
• For year 1999, lowest net excess air carrying
  capacity occurs in January with a value of -12962
  tons/year. For other months such as February,
  March, April, October, November and December, the
  air pollution problems are all very serious, and
  the net excess air carrying capacities are all
  negative values for all these month.
• If calculated by annual average air quality, the
  net excess air carrying capacity is 5562
  tons/year.

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Strategies when Total Emission Control Policy
Applied in Each Air Quality Regions

• Major control strategies were evaluated for their
  feasibilities when Total emission control
  strategy applied in each air Quality regions.
•  
• Possible strategies that can be used include
• 1. Reasonably available control Technology,
• 2. Best available control Technology,
• 3. New Source Performance Standards,
• 4. New Source Review, and
• 5. Prevention Significant Deterioration.