Summary #
Alkalinity is the capacity of water to neutralize acid. It is one of the most important measurements for assessing AMD-impacted streams because it indicates whether a stream has enough buffering to resist pH drops. This page explains what alkalinity measures, common units, and why it matters for water quality.
Alkalinity measures the buffering capacity of the stream, or its ability to resist changes in pH. Carbonate and bicarbonate are the most influential compounds in determining alkalinity. Streams with low alkalinity levels are not able to resist pH changes. This leads to drastic effects on the aquatic life if acid rain falls into the stream or it is affected by AMD. Stream that naturally run through limestone or are fed by groundwater filtered by limestone have much higher natural alkalinity levels.
The picture below is an example of an alkalinity test kit. As with most HACH tests the directions are very easy to read and follow. The tests for alkalinity and acidity are very similar. The main difference lies in the reagent used to titrate the sample to a color change. Or, in English, the chemical that is added (drop wise) to the sample until it changes color as directed in the instructions.
HACH Company provides a catalogue of chemical water testing kits and supplies http://www.hach.com/
Other tests, including and/or in addition to those described above, may be appropriate for the watershed in your area. The indicators the were chosen as points of study while making your monitoring plan are a good way to decide what tests need to be performed.
Sources/Links (as provided in the source text):
- http://www.hach.com/
Related Pages #
- Developing a Monitoring Plan — Structuring your monitoring program
- Buffering (Chemistry Fundamentals) — Alkalinity and buffering capacity
- Acids, Bases, and pH (Chemistry Fundamentals)
Source and Last Reviewed #
Source: AMR Clearinghouse (amrclearinghouse.org). Migrated to AML-Connect. Last Reviewed: 2026-03-13.
[Admin note: Some external links in this article may be outdated. Verify before relying on them. Flag dead links for removal or replacement.]
Tags: alkalinity, monitoring, sampling, amd
