SNAP

Swatara Creek near Hershey, Pa.

Overview
  • Station Id: 01573560
  • County: Dauphin
  • Drainage Area: 484 sq.mi.
  • Station Coordinates: 40.287°, -76.678°
  • Period of record: 10/84 to 12/89 & 10/04 to present
Location Description

10/84-12/89 - Station is located at a bridge 0.7 miles downstream of Route 39 bridge and approximately 100 feet upstream of the confluence of Spring Creek and Swatara Creek bridge near Union Deposit. Gage is located on east bank, 0.5 miles upstream of Route 39 bridge.

Data

2016 Land Use

Urban Agricultural Agricultural Forested Other
Row Crops Pasture/Hay Total
14% 24% 15% 39% 43% 3%
Site Drainage Area

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Clear
2019 Flow Normalized Trends
Trend period (Water Year*) 2005-2019
Trend & Direction NS – Not significant,  UP – Increasing trend,  DOWN – Decreasing trend
Hypothesis Test significance level (i.e. α) 0.1
* Water Year runs from October 1st to September 30th of the following year
Likelihood Descriptor Range of values**
HL (Highly Likely) ≥0.95 and ≤1.00 
VL (Very Likely) ≥0.90 and <0.95 
L (Likely) ≥0.66 and <0.90
ALAN (About as Likely as Not) >0.33 and <0.66
** Values represent the posterior mean estimate of the probability of a trend
Swatara 2005-2019 Flow Normalized Concentration (mg/L) Flow Normalized Load (Millions Kg/yr)
Likelihood Test Likelihood Test
Parameter Change Value Descriptor Trend Change Value Descriptor Trend
Total Nitrogen -1.141 0.99 HL DOWN -0.543 0.99 HL DOWN
Nitrate-Nitrite -1.206 0.99 HL DOWN -0.676 0.99 HL DOWN
Ammonia -0.021 0.99 HL DOWN -0.011 0.79 L DOWN
Dissolved Nitrogen -1.158 0.99 HL DOWN -0.583 0.99 HL DOWN
Nitrate-Nitrite -1.170 0.99 HL DOWN -0.629 0.99 HL DOWN
Ammonia -0.016 0.99 HL DOWN -0.008 0.75 L DOWN
Total Phosphorus -0.008 0.74 L DOWN -0.003 0.60 ALAN NS
Particulate Phosphorus 0.000 0.50 ALAN NS 0.000 0.52 ALAN NS
Dissolved Phosphorus -0.009 0.97 HL DOWN -0.005 0.77 L DOWN
Orthophosphate -0.007 0.97 HL DOWN -0.003 0.77 L DOWN
Total Organic Carbon -0.378 0.91 VL DOWN -0.574 0.87 L DOWN
Total Suspended Solids -1.229 0.56 ALAN NS -9.056 0.72 L DOWN
Suspended Sediment 2.557 0.52 ALAN NS 3.077 0.62 ALAN NS