DOI: 10.6073/pasta/de140c21d863b12baf7fabf27e41574d
title: Stream chemistry for core sites in Gwynns Falls: concentration of Cl, NO3, PO4, total N and P, SO4, dissolved oxygen, E. coli, plus temperature, pH, clarity and turbidity

description: In the Baltimore urban long-term ecological research (LTER) project, (Baltimore Ecosystem Study, BES) we use the watershed approach to evaluate integrated ecosystem function. 
      
      
          The LTER research is centered on the Gwynns Falls watershed, a 17,150 ha catchment that traverses a gradient from the urban core of Baltimore, through older urban residential (1900 - 1950) and suburban (1950- 1980) zones, rapidly suburbanizing areas and a rural/suburban fringe.
      
      
          Our long-term sampling network includes four longitudinal sampling sites along the Gwynns Falls as well as several small (40 - 100 ha) watersheds located within or near to the Gwynns Falls. The longitudinal sites provide data on water and nutrient fluxes in the different land use zones of the watershed (rural/suburban, rapidly suburbanizing, old suburban, urban core) and the small watersheds provide more focused data on specific land use areas (forest, agriculture, rural/suburban, urban). Each of the gaging sites is continuously monitored for discharge and is sampled weekly for chemistry. Additional chemical sampling is carried out in a supplemental set of sites to provide a greater range of land use. Weekly analyses includes nitrate, phosphate, total nitrogen, total phosphorus, chloride and sulfate, turbidity, fecal coliforms, temperature, dissolved oxygen and pH. Cations, dissolved organic carbon and nitrogen and metals are measured on selected samples. 
      
      
          This dataset presents stream chemistry from the core long-term monitoring sites.  Sampling began at most of these sites in Fall 1998 and is ongoing.  
      
      
          A detailed description of these sites is posted at: http://md.water.usgs.gov/BES/.
      
      
          Streamflow data for this site are posted at: http://waterdata.usgs.gov/md/nwis/nwisman?site_no=01583570
      
      
          Codes and Abbreviations
      
          1 - GFGL - Gwynns Falls at Glyndon (grab samples) - Suburban headwaters - 15-Oct-98 - ongoing
      
          2 - GFGLcomp - Gwynns Falls at Glyndon (ISCO sampler) - Suburban headwaters - 30-Jan-09 - ongoing
      
          3 - GFGB - Gwynns Falls at Gwynnbrook Avenue (Delight) - Suburban - 15-Oct-98 - ongoing
      
          4 - GFVN - Gwynns Falls at Villa Nova (grab samples) - Suburban/urban boundary - 15-Oct-98 - ongoing
      
          5 - GFVNcomp - Gwynns Falls at Villa Nova (ISCO sampler) - Suburban/urban boundary - 1-Apr-08 - ongoing (with gap from June 2002 to January 2004)
      
          6 - GFCP - Gwynns Falls at Carroll Park - Urban - 15-Oct-98 - ongoing
      
          7 - POBR - Pond Branch forested reference site - Forested reference - 15-Oct-98 - ongoing
      
          8 - BARN - Baisman Run at Ivy Hill Road - Suburban unsewered - 4-Dec-98 - onging
      
          8 - MCDN - McDonogh agricultural site - Agricultural - 9-Dec-99 - ongoing
      
          9 - DRKR - Dead Run at Krome Avenue - Urban - 24-Nov-98 - ongoing
      
          10 - MAWI - Maidens Choice at Wilkens Avenue - Urban - 18-Feb-04 - ongoing
      
          11 - RGHT - Rognel Heights (grab samples) - Urban - 25-Feb-99 - ongoing
      
          12 - RGHTisco - Rognel Heights (ISCO sampler) - Urban - 18-Feb-02 - ongoing
      
          13 - GRGF - Gwynns Run at Gwynns Falls - Urban - 27-Aug-01 - onging
      
          14 - GFuGR - Gwynns Falls above Gwynns Run - Urban - 21-Jan-04 - ongoing
      
          15 - CRBR - Cranberry Branch - Exurban - 2-Jun-11 - ongoing
      
          16 - JBHH - Jennifer Branch at Hartford Hills - Suburban - 12-Aug-03 - 5/11/2010
      
          17 - JBNW - Jennifer Branch at Northwind - Suburban - 12-Aug-03 - 6/8/2010
      
          18 - JBON - Jennifer Branch at Ontario - Suburban - 12-Aug-03 - 6/8/2010
      
          19 - LANV - Lanvale street station in WS263 (grab samples) - Urban - 6-Apr-04 - 5/4/2010
      
          20 - LANVisco - Lanvale street station in WS263 (ISCO sampler) - Urban - 1-Apr-04 - 5/7/2009
      
          21 - BALTisco - Baltimore street station in WS263 (ISCO sampler) - Urban - 1-Apr-04 - 5/7/2009
      
          22 - BALT - Baltimore street station in WS263 (grab samples) - Urban - 6-Apr-04 - 5/4/2010
      
          23 - GRuTW - Gwynns Run above trash weir - Urban - 20-Jun-06 - 25-Jul-06
      
      
      
          Column,Variable (units)
      
          A,Date
      
          B,Year
      
          C,Julian Date
      
          D,Site
      
          E,Cl (mg/L)
      
          F,NO3 (mg N/L)
      
          G,PO4 (ug P/L)
      
          H,SO4 (mg/L)
      
          I,TN (mg N/L)
      
          J,TP (ugP/L)
      
          K,time
      
          L,stage (ft)
      
          M,temperature (deg C)
      
          N,dox (mg/L)
      
          O,ph
      
          P,clarity
      
          Q,Turbidity (NTU)
      
          R,Ecoli (CFU/100 mL)
      
      
      
          Methods:  
      
      
          Samples are collected weekly at an established sampling location at each station. Sampling locations were chosen based on adequate concentration of flow, proximity to weir and staff gage, and low vulnerability to disturbance. Samples are collected and stored in polyethylene bottles. 
      
      
          Weekly analyses includes nitrate, phosphate, total nitrogen, total phosphorus, chloride and sulfate, turbidity, fecal coliforms, temperature, dissolved oxygen and pH. Cations, dissolved organic carbon and nitrogen and metals are measured on selected samples.
      
      
          Samples for anion and cation analysis are filtered (0.45 micron). Samples for total N, total P, turbidity, and fecal coliform analysis are not filtered. 
      
      
          Every six weeks, samples are shipped to the Cary Institute of Ecosystem Studies (CIES) for anion, cation, TN, and TP analysis. Fecal coliform analysis was done from October 2001 through September 2004 in Karin Raedel's laboratory at UMBC. These analyses are described below.
      
      
          One blank from the laboratory distilled water source is prepared each week and stored along with the samples. Once every six weeks one extra filtered sample is collected at three stations, Carroll Park, Villanova, and Glyndon, for percent recovery (spike) analysis. Back at the UMBC lab, the extra bottle is spiked with one mL each of a 1000 ppm NO3- and a 1000 ppb PO4- standard per 100 ml of solution; the cation bottle is spiked with a combined nitrate and phosphate standard and stored and analyzed with other samples. Samples are stored at 4 degrees C. 
      
      
          Concentrations of nitrate, chloride and sulfate are analyzed on a Dionex LC20 series ion chromatograph. Concentrations of phosphate are analyzed on a Lachat Quikchem 8000 flow injection analyzer. 
      
      
          Total nitrogen and phosphorus are analyzed by persulfate digestion followed by analysis of nitrate and phosphate on a Lachat Quikchem 8000 flow injection analyzer. If the value for total N is more than 0.10 mg N L-1 less than nitrate-N, the total N value for that sample is set to the nitrate value. If the value for total P is more than 0.01 mg P L-1 less than the phosphate P, the total P value for that sample is set to the phosphate value.
      
      
          An HF Scientific DRT-15CE turbidimeter is used to analyze turbidity. 
      
      
          Samples were analyzed for fecal coliform concentration using Micrology Laboratories' Coliscan EasyGel method from October 2001 through September 2004.
      
      
          Temperature, pH, conductivity and dissolved oxygen are measured using a handheld meter during weekly visits for sample collection.