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Showing posts from August, 2016

Groundwater hydrology modeling: the relation among stream, groundwater and surface runoff

Stream discharge is an important component in hydrology. Yet stream discharge is commonly studied in surface hydrology. In recent decades, it has been recognized that groundwater also interact with stream water throughout the year.

In groundwater modeling, stream routing is explicitly modeled as a groundwater boundary condition.
In general, several data are required for a successful simulation. Here I will only discuss a little bit related to water itself, to say, what kind of sink or source of the water in stream routing should be considered.

First, a stream segment/reach may received upstream discharge.

Second, a stream can also receive direct precipitation from the sky. But this term is usually omitted some the total amount may not be significant.

Third, a stream may also lose water from evaporation. Similar to direct precipitation, this term is usually omitted as well.

Forth, stream also receive later flow, it can be surface runoff and subsurface runoff (soil zone inter-flow). Man…

Surface water hydrology: build the relationship between river gage height and discharge

Both gage height and discharge rate are important factors in surface water hydrology.
For most of the time they are closely coupled.
When one of them is missing, we can always estimate the other using some relation algorithms.
To date, there a few commonly used relation algorithms. For example:
https://en.wikipedia.org/wiki/Rating_curve

Here are more materials:
http://water.usgs.gov/edu/streamflow3.html

Based on these relations, a simple test was run to illustrate and estimate the discharge based on gage height.

Figure 1. Gage height-discharge relation curve. The blue crosses are observed gage height-discharge data. The red crosses are calculated after "parameter estimation" using curve fitting method.