Hydrology of the Pastaza Basin

1
Hydrology of the Pastaza Basin

• An Oil Spill Risk Assessment
• In the Peruvian Amazon
• by
• Anne Mariah Tapp

2
Study Area
3
Northern Peruvian Oil Pipeline Constructed 1974
and not maintainedTransports 5400 m3/day of
heavy crude oil

• Project Goal- Use ArcGIS and ArcHydro to
  determine
• The areas potentially impacted by a break in the
  pipeline
• The travel time of the oil to the impacted
  locations

4
(No Transcript)
5
Source Data-WaterGAP Model

• Rainfall-Runoff Model
• Stream Network and Catchments Delineated
  Worldwide from 30m resolution DEMs
• .5 Resolution
• Assumes velocity of 1 m/s for ALL water-bodies
• Provides discharge data (m3/s) for each stream
  segment.

6
(No Transcript)
7
Waterbodies in the Pastaza Basin

• Whitewater River- Pastaza

• Blackwater Tributary-Huasaga

8
Comparison of Stream ProfilesMain Pastaza
Channel and Tributaries

• Range of velocities for points
• along the main Pastaza
• 2.4 to 0.6 (m/s)

• Range of velocities (m/s) for measured
  tributaries
• -1.3 to 0.6 (m/s)

9
Comparison of Discharge Calculated by Different
Methods
10
Methods

• Calculate total stream length from pipeline
• Assume oil flows with water
• Create geometric network and set flow direction
• Trace downstream from potential break sites
• Calculate travel time (days) by dividing velocity
  (meters/day) by length (meters).

11
(No Transcript)
12
Remaining Work

• Evaluate behavior of heavy crude oil
• Possibility of Evaporation and Precipitation
• Tailor model to reflect this behavior
• Currently model assumes travel with water.
• An inaccurate method of modeling oil
• However, provides a basic risk assessment.