Condition Measurement

Measuring a Water Bodies Condition

Peters Creek Large PA

All surface water (lake, stream, wetland) in Pennsylvania is assigned a list of uses. The ability to support aquatic life is on the list for all of the surface water bodies of our state.

How do we determine whether a given water body is adequate to support a specific use?

For each use, a list of measurable standards has been developed. Lets look at one of the aquatic life uses, Trout Stocked Fishery, and examine the standards for this use.
Brook Trout

Trout Stocked Fishery
Maintenance of stocked trout from February 15 to July 31 and maintenance and propagation of fish species and additional flora and fauna which are indigenous to a warm water habitat.

A few too many big words here.
Maintenance means that if you stock trout, conditions are adequate that they will survive from February 15 to July 31.

Propagation of fish species indigenous to warm water habitats means that the water body provides conditions such that fish normally found in warm water bodies in our area can survive and produce offspring.

The water body should also be able to support other flora(plants) and fauna(animals) that are native to western Pennsylvania's warm water streams, lakes, and wetlands.

What would we measure to determine whether a stream meets the requirements of a Trout Stock Fishery, that is, what specific standards must be met?


6.0-9.0 inclusive

Dissolved Oxygen

For period February 15 to July 31 of any year, minimum daily average of 6.0 mg/l; minimum 5.0 mg/l. For remainder of year, minimum daily average of 5.0 mg/l; minimum 4.0 mg/l

Total Residual Chlorine

Four-day average 0.011 mg/l; 1 hr average 0.019 mg/l

Total Dissolved Solids

500 mg/l as a monthly average value; maximum 750 mg/l

Total Alkalinity

Minimum 20 mg/l as CaCO3, except where natural conditions are less. Where discharges are to waters with 20 mg/l or less alkalinity, the discharge should not further reduce the alkalinity of the receiving stream.


Table below lists very specific temperature requirements over course of the year. Water temperature should not exceed Max Temp at any time during given period.
January 1-31 40
February 1-29 40
March 1-3146
April 1-15 52
April 16-3058
May 1-15 64
May 16-31 68
June 1-1570
June 16-30 72
July 1-31 74
August 1-1580
August 16-3087
September 1-1584
September 16-3078
October 1-15 72
October 16-3166
November 1-15 58
November 16-3050
December 1-3142

What can cause a water body to not be able to meet these standards, that is, what types of pollutants can degrade a stream so that it is not suitable for Trout Stocking?