A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

Bailer
A cylinder of steel with a valve in the bottom that is used to remove rock cuttings or sediments from a hole being drilled by the cable tool method. A bailer may also be used to clean out a hole drilled by any method.

Bank Filtration
The abstraction process for water supply that benefits from "pre-treatment filtration" of surface water by removing it from river bank wells or infiltration galleries rather than directly from surface water.

Bank Seepage
The natural diffuse discharge of groundwater into a river or lake along its banks. If concentrated in a particular area, a seepage may more accurately be called a spring.

Bank Storage
Water stored in river bank sediments. At times of high water flow in rivers, water may flow laterally into the stream bank sediments adjacent to the river. This "stored" water may flow slowly back into the river or be utilized by wells.

Bankfull Discharge
Stream flow that completely fills the stream channel to the top of its banks.

Base
Used in water chemistry. A substance that has a pH of more than 7, which is neutral. A base has less free hydrogen ions (H+) than hydroxyl ions (OH-).

Baseflow
The proportion of water flowing in streams and rivers that comes from ground water. River flow during dry weather conditions may be virtually all baseflow. At least 40% of all the annual flow total of rivers in the U.S. is derived from baseflow.

Basin
(see drainage basin, watershed)

Bedrock
The solid, but often fractured and fissured, rock formations that occur beneath soils, unconsolidated sediment deposits or weathered materials. Exposed bare rock is bedrock at the surface. Sediments or weathered material overlying bedrock is sometimes called regolith or overburden.

Bentonite
A colloidal clay of volcanic origin used as the main ingredient in drilling fluid (drilling mud) used in rotary well drilling processes and also used as a grouting medium to seal well casing in the drilled hole. Most bentonite in the U.S. is mined in Wyoming.

Best Management Practices (BMP)
Sensible land management strategies that can reduce the potential for non-point source pollution from dissolved or particulate contaminants.

Bicarbonate
Alkilinity in water is usually composed of bicarbonate and is reported as mg/L CaCO3.

Bit
The cutting tool used in well drilling. Drill bits vary in complexity from the simple chisel used in cable tool drilling to tri-cone bits used in mud rotary operations.

Brackish Water
Water that is salty, but less salty than seawater. Seawater has 35,000 mg/L of salts, and is described a saline.

Brine
Salty water with more than 10,000 mg/L of salts (principally sodium chloride).