Donegal TU Determines Temperature Profile of Lititz Run

Reproduction of wild trout in a stream is the ultimate goal for many individuals interested in cold-water conservation and fly-fishing. The Donegal Chapter of Trout Unlimited has done a significant amount of work on Lititz Run in Lancaster County, Pennsylvania to improve water quality and provide habitat for trout. Trout have been stocked in Lititz Run in the spring of the year but the question remains can trout reproduce and grow as wild trout? To answer that question Donegal TU needed to determine whether or not Lititz Run is a cold-water stream. Is the temperature cool enough in Lititz Run during the summer months to support a population of wild trout?

To answer this question Donegal TU in partnership with Warwick Township developed a plan to monitor water temperature in Lititz Run from April 1, 2004 to November 1, 2004. Eight HOBO Water Temp Pro Loggers were purchased from Onset Computer Corporation in Pocasset, Massachusetts.

The HOBO Loggers are designed to remain submersed in water and record water temperature at regular intervals of time as determined by the user. Beginning south of Route 501 in Lititz, HOBO Loggers were installed at eight locations from Route 501 south to the Ed Hess farm. Each HOBO, as pictured below, was installed by pounding a three foot section of rebar into the stream bed and then using wire HOBOs were attached to the rebar permitting the HOBOs to float below the surface approximately ten inches downstream from the rebar.

Using BoxCar Pro 4.3 software each logger was programmed to record water temperature every four hours throughout a 24-hour day. At the beginning of each month data was downloaded to a computer using an infrared sensor as shown below.

Data was analyzed to show the average temperature recorded at each site for the following times through out a 24 hour day: 2:00; 6:00; 10:00; 14:00; 18:00 and 22:00 hours. Data was unavailable for July at the writing of this report, therefore this report will show data for the month of June. Eight HOBO Loggers were originally installed but an unidentified individual pulled one of them out of the streambed, therefore this report will show data for seven HOBO Loggers.

Site one as shown below was located just south of Route 501 in Lititz. Site 2 was located adjacent to a parking lot in Lititz. Site 3 was located south of Lititz above a trout hatchery operated by a private group of Lititz sportsman. Site 4 was located adjacent to Riparian Park below the Lititz Sewage Treatment plant. Site 5 was located at the upper end of Millport Conservancy and the HOBO at site 6 at the lower end of the conservancy was found lying on the bank. Site 7 was located on the Baum farm and site 8 was located on the Hess farm.

Data for the average water temperature at the above seven sites for June 2004 are shown below:

Lititz Run begins from a spring, which bubbles out of the ground in the town of Lititz. Site 1 was located approximately .25 miles below the source so one would expect the water temperature at site 1 to be the coolest temperature in Lititz Run. As the water flows south of Lititz it moves through open pastureland before entering a 1-mile stretch of land in Millport Conservancy with moderate shade from trees. Below Millport Conservancy the water moves through open pastureland through several farms to the Ed Hess Farm. As one would expect the water becomes progressively warmer going downstream as shown in the chart below:

The coolest temperature at all sites was recorded at 6:00 AM. The warmest temperature near the source occurred at 2:00 PM and the warmest temperature in the lower reaches in open pastureland occurred at 6:00 PM.

The daily fluctuation in average temperature near the source (Rt 501) was 1.91 F and on the Hess Farm was 5.68 F. The average temperature did not exceed 66 F in the month of June.

It was interesting to note that a temperature spike at site 2 (Parking Lot) occurred on June 15 as seen below. The temperature at 2:00 PM was 61.54 F and the temperature at 6:00 PM was 74.16 F. This was a fluctuation of 12.62 F from 2:00PM to 6:00PM.

Site 2 is located near a parking lot in Lititz. The air temperature on June 15 was 87 F. At 5:19 PM WGAL TV recorded the wind speed in Lancaster (9 miles south of Lititz) at 38 MPH. Rain fall recorded at the sewage treatment plant in Lititz on June 15 was 0.50 inch.

This suggests that a thunderstorm went through Lititz on June 15. Given that the air temperature was 87 F the parking lot adjacent to Lititz Run was warm on June 15. The data suggests that as rain fell on the parking lot the temperature of the water moving over the parking lot increased and as run off water entered Lititz Run the water temperature in Lititz Run increased 12.62 F. 

In summary HOBO Water Temp Pro Loggers may be used to effectively monitor water temperature in a stream. The preliminary data suggest that Lititz Run is a cold-water stream given that the average water temperature did not exceed 66 F in the month of June. If cool water temperatures continue through July and August the water temperature in Lititz run may be cool enough to support a population of wild trout. Obviously water temperature is just one factor contributing to the successful reproduction of wild trout. Other factors such as dissolved oxygen; food supply, sediment, water chemistry, habitat, and gravel-beds play a vital role in the reproduction of wild trout.

Donegal TU will continue collecting data throughout next year to provide a profile of the stream’s temperature for two consecutive years and determine whether or not water temperature in Lititz Run is cool enough to support a population of wild trout.