Tool T01 · Travel Time

How old is your water?

Groundwater moves slowly. Pick an aquifer, adjust the distance from recharge, and see how long it took a single drop to reach your tap.

Aquifer

Clean quartz sand — high conductivity, moderate porosity.

Distance from recharge zone20 mi

1 miMemphis → Fayette ~20 mi80 mi

Hydraulic gradient0.0010

Typical Memphis Sand: ~0.001. Steeper = faster flow.

Your water fell as rain about

1,200 yr

ago · through 20 miles of memphis sand

velocity = 0.240 ft/day · 88 ft/yr

200

years ago

American Civil War

1,000

years ago

Norse in North America

2,500

years ago

Ancient Rome founded

The formula

v = K × i / n_eff t = L / v

v = average linear (seepage) velocity · K = hydraulic conductivity · i = hydraulic gradient · n_eff = effective porosity · L = flow path length

This is Darcy's Law for groundwater travel time. It assumes purely advective flow through a homogeneous aquifer — real aquifers have dispersion, heterogeneity, and preferential pathways that make travel times distributions rather than point estimates.

Data:USGS·CAESER (University of Memphis)

← Back to Meet the Aquifer

Loading tool…