Water quality data for Fall Creek (Tompkins County, NY) sampling sites: 1972-1995

This data base is a compilation of water quality data collected in the period 1972 through 1995 from the Fall Creek watershed (including USGS site 04234000) and its subwatersheds. I am deeply grateful to the many research associates, graduate students, post docs and fellow faculty who helped collect and interpret the data. In 1970 Cornell University received a grant from the Rockefeller Foundation to study runoff from land and its impact on water quality. A multidisciplinary team was developed and led by Professor Robert J Young. In 1975-6 this research was summarized in the following: Johnson, Arthur H. 1975. Phosphorus export from the Fall Creek watershed. Ph D thesis. Cornell University Library, Ithaca NY. Johnson, Arthur H., David R. Bouldin, Edward A. Goyette, and Anne Hedges. 1976. Phosphorus loss by stream transport from a rural watershed: Quantities, processes and sources. J. Environ Quality. 5:148-157. Johnson, Arthur H. David R. Bouldin, Edward Goyette and Anne Hedges. 1976. Nitrate dynamics in Fall Creek New York. J Environ Quality. 5:386-391. Johnson, Arthur H, David .R. Bouldin, Gary W. Hergert. 1975. Some observations concerning preparation and storage of stream samples for dissolved inorganic phosphorus. Water Resources Research. 11:559-562. Porter, Keith S. and Robert J. Young eds. 1976. Nitrogen and phosphorus. Food production Waste and the Environment. Ann Arbor Science Inc. Ann Arbor Mi. (ISBN 0-250-40111-8) Information Bulletin 127 (Bouldin, D.R. et al. Lakes and Phosphorus inputs. A Focus on Management. New York State College of Agriculture and Life Sciences. Cornell University, Ithaca NY). Since the above project was finished, monitoring has continued at irregular intervals as financing became available. The archived files describe the results of analysis of over 3000 water samples, 1972- 1995, concerned with land runoff and the lakes in central NY. Major findings follow. Three P fractions were measured: MRP, TDP and TP. MRP was measured on centrifuged samples without treatment and is presumed to be mostly inorganic P in solution. TDP is measured on centrifuged samples after oxidation of organic forms of P and hence is total P in solution. TP is particulate P plus TDP. Usually MRP and TDP are considered the major forms used by algae. (Porter, 1976 pp 61-120, Information Bulletin 127; see also ms2_anal, ms1_intP.doc at http://hdl.handle.net/1813/2547). The average TDP in about 1500 samples from Fall Creek was 0.026 mg per liter, loading was about 4400 Kg P or about 0.13 kg/ha/year . About ½ was MRP. Total P was about 0.140 mg/liter. Approximate sources of TDP are as follows: 50% from inactive agriculture and forest, the other 50% attributed to human activities of which about half was from diffuse sources and half from point sources. MRP concentrations in runoff from 16 subwatersheds varied from 0.006 to 0.050 mg/l. The TDP in Cayuga Lake ranges from 0.005 to 0.020 mg per liter. The TDP load in Kashong Creek (a tributary to Seneca Lake) was 0.25 kg/ha/year (about twice that from Fall Creek). (Porter, 1976 pp 61-120, Information Bulletin 127). NO3 loading from Fall Creek is about 5.5 kg/ha /year; this is about 80% of the input of inorganic N in precipitation. This is a consequence of mosaic of sources varying widely in concentration. NO3 loading from 9 subwatersheds in Fall Creek varied from 1 to 7.7 kg/ha/year; no sample containing more than 10 ppm was found. (Porter 1976 pp 108-114). Streams draining wooded areas without human habitations or active agriculture have NO3 concentrations similar to those found in the Catskill and Hubbard Brook in NY and loadings on the order of 20 % (~1 kg/ha/year) of the inputs of inorganic N from precipitation and (see ms5_biog.doc; online at http://hdl.handle.net/1813/2547) . There is presently no evidence of "forest saturation with N" in the Fall Creek watershed. There are unlikely to be more than a very few small streams in the Fall Creek watershed in which the concentration of NO3-N will exceed the 10 ppm public health standard. However some aquifers under heavily fertilized fields (such as those on the Harford T&R Center) may contain more than the public health standard. (ms9_NO3.doc, ms5_biog.doc; online at http://hdl.handle.net/1813/2547). Estimates of evapotranspiration (ET) for Fall Creek did not change statistically during the period 1926-1996 as estimated by annual precipitation input minus stream outflow, indicating that land use changes were not important in influencing ET in this watershed (ms_15_ET.doc; online at http://hdl.handle.net/1813/2547). Cl was used as tracer of effects of road salt. During late spring-summer-early fall when road salt was not applied, the flow weighted Cl concentration increased from about 11 ppm in 1972 to 19 ppm in 2003. The Cl concentration of samples taken during snow melt or winter rain following applications of road salt were as high as 60 to 70 ppm Estimated flow weighted concentration of Cl delivered to Cayuga Lake is 24 ppm (ms16_slt.doc; online at http://hdl.handle.net/1813/2547). The most important sampling protocols are the following: Concentrations of constituents in stream water vary seasonally and/or with flow intensity. This means that a) timing of sampling must be carried out during all seasons and over all flow regimes, b) amounts of various substances such as N, P and sediment transported to lakes and reservoirs are the product of flow multiplied by concentration which means that flow measurements must be made at the same time as samples are taken for analytical determination. With respect to TDP, point sources will be most evident under low flow conditions while non- point sources will be most evident under high flow conditions. Loading of non point sources is thus very much dependent on the 10 % to 20% of the time when highest flow conditions occur. The most important conclusion I reached about watershed management is the following. Watershed management requires detailed knowledge about the cost of several management options per unit of decrease in loading/ concentration. Our experience was that the various human activities in sub watersheds were correlated with each other. This meant that statistical analysis of correlations between loading of N and P were useless in identifying the management options which would be most beneficial. This also means that commonly used procedures for validating models are useless in terms of developing management strategies (Ms12_mgm.doc; online at http://hdl.handle.net/1813/2547)