Math Conversion

Question

The drainage basin of the Delaware River encompasses about 35,500 km^2 (= 35 x 109 m^2). The average annual precipitation for the drainage area is about 44 inches/year (= ~1.1 m/yr) and the evaporation reaches 23 inches/year (= ~0.6 m/yr). What is the flow rate of total flow at the mouth of the Delaware Bay? your units must be in m^3/seconds

Answer 1

So we are given the area: 35.5 x 10⁹ m²

We want to find: Some flow rate in m³s^-1

SOLUTION:

1. Find avg. precipitation in terms of volume per year
2. Find avg. evaporation in terms of volume per year
3. Combine to find flow rate per year
4. Use dimensional analysis to convert to per second. Basically, we multiplying by 1/1, so the units change, but the actual value doesn't
5. Years > Days > Hours > Minutes > Seconds
6. 1 year * (365 days/1 year) * (24 hrs/1 day) * (60 minutes/ 1 hour) * (60 seconds/1 minute) = 3.1536x10⁷ seconds in 1 year
7. Answer should be in m³s^-1