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 maintained Transports 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

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.

7. Waterbodies in the Pastaza Basin
Whitewater River- Pastaza
Blackwater Tributary-Huasaga

8. Comparison of Stream Profiles Main 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).

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.