Geol 220: GROUNDWATER HYDROLOGY. Co-Lecturers: Dave Goorahoo and Richard Soppe. Lecture 1- Introduction to Hydrology Jan 28 , 2002. Outline. Introductions- Lecturers Students. Agreement on Class Schedule. Course Syllabus . Introductory Lecture and Definitions (Dave).
Dave Goorahoo and Richard Soppe
Lecture 1- Introduction to Hydrology
Jan 28 , 2002
Drainage, Flood control
Soil degradationWhy Study Groundwater Hydrology?
Ideally, it is not possible to separate reasons for understanding groundwater hydrology in categories as listed, since water links the major components of our ecosystem as part of the:
Aircontinuum.The HYDROLOGIC CYCLE maintains the
Referred to as Unsaturated Zone
Underground or Subsurface water
SATURATED ZONE or PHREATIC ZONE
(Generally defined as the GROUNDWATER)
Water Table :Surface in a geologic medium where water pressure equals atmospheric pressure. Often used as the boundary between the Unsaturated and Saturated Zones.
Vadose Zone:The geologic media between the land surface and the regional water table. Often used as synonymous with the Unsaturated zone
Volumetric water content q:Volume of water per unit volume of bulk soil. Like porosity n, q is reported as a decimal or percent. For Saturated zone q =n, and q < n for Unsaturated zone.
Infiltration I :Rate at which water enters the soil from the surface.
If water application rate F is lower than the infiltration the soil I,then water enters into soil and there is no ponding.
If F> I then ponding results; If F>> I, then run off results!
Hydraulic Conductivity K :Rate at which water moves through the soil. Given in cm/s, m/s, cm/day, in/hr or any equivalent units of velocity,
Can vary in the x, y or z directions, as well as in the Unsaturated and Saturated zones.
Darcy’s Law earth’s surface can be classified as
Darcy’s law: The flow of water through a porous medium is in the direction of, and at a rate proportional to, the driving force (i.e. the hydraulic gradient) and also proportional to the ability of the conducting medium to transmit the water (hydraulic conductivity).
Using x, y and z coordinates, we can write flux as earth’s surface can be classified as
Where q is the flux (m/s), H is the hydraulic head (m), and grad H the gradient of the hydraulic head.
In saturated soils K is defined as the saturated hydraulic conductivity, Ks.
In Unsaturated soils,K is the unsaturated hydraulic conductivity.
Stop here on 01-28-02 earth’s surface can be classified as