Introduction

The purpose of this exercise is to examine three descriptions (that I created) that describe the consumption of organic matter in streams and then create your own that has spatial layers.

Each of these "models" describe the conditions that lead to an oxygen-sag and recovery downstream. Because the stream is flowing, time is the same as distance.

the description in lecture 18

an Excel model - streeter-phelps.xls

a STELLA model - stream-dilution-decay.stm

Description of Exercise

Create your own STELLA diagram of this process that takes into account oxygen concentration and organic concentration in multiple "cells" or layers going down stream. Instead of time being related to distance, you will have a separate set of boxes for each distance downstream.

Your diagram should include all the features that you think would be required to eventually create a mathematical model (but you aren't supposed to do that). You should do that for 5 layers.

Provide a short written description with your model diagram.

last modified March 10, 2008