Last updated: July 8, 2020

Math Skill: Addition & Subtraction (decimal numbers)

Science Skill: Earth Water

Grade level:  4th5th grades

Area level: Community-scale

Environmental Area: Water

Purpose: Understand how water is managed in Evansville and develop awareness of water conservation



The City of Evansville’s Water Department extracts water from the Ohio River to meet demands in and around the City. To ensure drinking water quality, the Water Department monitors for nearly 100 contaminants, including bacteria, metals, and pesticides at its water filtration plant.  At the plant, water is treated with several chemicals, including aluminum sulfate, caustic, fluoride, carbon, chlorine dioxide, and ammonia, to remove contaminants and improve the water quality. The method that applies chlorine dioxide for treatment of drinking water was invented at the Evansville Filtration Plant in 1989.

In total, the Evansville Water Department has 8 storage tanks and 1,000 miles of water mains in the system. The Department treats, on overage, about 25million gallons of water per day from the Ohio River. Evansville’s drinking water meets or exceeds all state and federal regulations so that it can be drunk without any home filters.

The Evansville Sewer Department manages the sewage system in the area that consists of 504 miles of sanitary sewer system (for human waste) and 318 miles of combined sewer system (for human waste and storm sewer). The sewage system begins with connecting pipes from residential and commercial buildings to larger underground trunk mains, which convey wastewater to two wastewater treatment facilities—the West and East Wastewater Treatment Plants.  The West Wastewater Treatment Plant has the capacity to treat 30.6 million gallons of wastewater from the western basins of Evansville per day, while the East Wastewater Treatment Plant has the capacity to treat 22.5 million gallons of wastewater from the eastern basins.

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City’s Educational Program

The Evansville Water and Sewer Utility offers educational program for students on Monday through Friday, year round.

Contact: Tim Hall at (812) 428-0568 between 7:30 a.m. and 4:00 p.m., Monday through Friday, for further information and scheduling.


The purpose of this activity is to enhance students’ skills in addition, subtraction, multiplication, and division of large numbers and/ordecimalnumbers. This worksheet uses data from 8 water storage tanks in Evansville. It provides two patterns to express the size of the tanks: One is expressed in gallons and the other is expressed in million gallons. Teachers can choose either one, depending on the skills they are focusing on in the class. The data was obtained from the Evansville Water and Sewer Department.

worksheet & answer key

Math Skill: Addition & Subtraction (large numbers)

Using data from 8 water storage tanks in Evansville, students are asked to answer questions that use addition and subtraction, inducing the size difference between two tanks and the total water storage capacity in Evansville. Use a worksheet I (large numbers) or II (decimal numbers) depending on the skills you are focusing on in the class.


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