Environmental Enlightenment #312
By Ami Adini - Issued June 26, 2019
This is a SHORT, LIGHT and SIMPLE newsletter. Its purpose is to rekindle in the initiated terminology they have once learned, and enlighten the uninitiated on terms they may have heard but never known the meaning of.
Groundwater Gradient and
Phase I Environmental Site Assessment
Gradient is the inclination of a riverbed, usually described as the number of feet the river drops per mile.
Water flows downhill.

Always?

Take a close look at the water in the creek as it bounces from rock to rock on the way down and you’ll see eddy currents going against the flow in various directions.
And so it does underground.

In the investigation of properties, we are interested in potential impacts from the neighbors: contaminated groundwater from an uphill (upgradient) source can migrate downhill (downgradient) into our property of concern.

The diagram below describes a case where a plume is migrating downgradient across two city blocks
Thus, in Phase One Environmental Site Assessment we search for properties that are located upgradient (uphill) to see if they have contaminated the groundwater. In this search, however, we do not ignore properties downgradient (downhill) from or cross-gradient (sideways) to our property, especially if they are nearby.

The reason is that within narrow zones, groundwater flow directions may vary from the general flow in the area.

There could be subterranean seismic faults:
In one case we had the retaining walls of a drainage channel reversing groundwater flow 180 degrees.
Map Data © 2019 Google
Therefore, when we identify sources that have contaminated groundwater in proximity to a property of interest, we may express concerns for migration of the contamination into the property, even if the sources are downgradient (downhill) or cross-gradient (sideways) when looking at the general flow of groundwater in the area.
You can find past issues of our "Environmental Enlightenment" at  amiadini.com  Wealth of information about environmental site assessments in the real estate transactions and issues concerning assessment and cleanup of contamination in the subsurface soil and groundwater.
Call me if you have any questions. There are  no obligations.
Ami Adini Environmental Services, Inc.
Environmental Consultants & General Engineering Contractors
California Lic. #1009513 A B HAZ ASB
818-824-8102 mail@amiadini.com

Ami Adini is a veteran environmental practitioner with over 40 years of experience. He carries a Bachelor of Science degree (B.Sc.) in Mechanical Engineering including academic credits in Nuclear and Chemical Engineering and postgraduate education in these fields. His career includes design and construction of nuclear plant facilities, chemical processing plants and hazardous wastewater treatment systems. He is a former California Registered Environmental Assessor Levels I & II in the 1988-2012 registry that certified environmental professionals in the assessment and remediation of environmentally impacted land, and a Registered Environmental Professional (REP) since 1989 with the National Registry of Environmental Professionals (NREP). He is a California Business & Professions Code Qualifying Responsible Managing Officer (RMO) in the General Engineering Contractor classification with Hazardous Substance Removal and Asbestos certifications, and president of AMI ADINI ENVIRONMENTAL SERVICES, INC. (AAES), a general engineering contractor and consulting firm specializing in environmental site assessments, rehabilitation of contaminated sites and removal of environmental risks from real-estate transactions. (Contact Ami for a complete resume.)  AAES provides practical solutions to environmental concerns using the highest standards of ethics and integrity while providing its clients with maximum return on their investments.