Stream water quality networks

Alexander et al. (1998) describe a comprehensive collection of water quantity and quality data by the USGS including measurements for 122 physical, chemical, and biological properties of water at 680 monitoring stations. These sites are from two water quality networks. The first is the Hydrologic Basin Network (HB1 which had previously been mentioned when referencing the work of Langbein & Slack (1982), who had termed it a

“benchmark” network. It comprises from 50 to 63 small, ii disturbed basins. The basins range in size from 5 to 5,200 km with a median size of 148 km Water quality sampling was conducted from about 1967 through to 1996. Water quality sampling at HBN sites was discontinued in 1997. The second water quality network is the National Stream Water Quality Accounting Network (NASQAN).

NASQAN historically comprises up to 618 sites, ranging in size from 3 to 3 million km with a median size of 10,400 km These sites represent mostly non-pristine basins, as the impetus for this network was to quantif3r long-term trends in national water quality and assess the sufficiency and effectiveness of pollution control legislation. This network was initiated in 1973, with just 51 sites. The number of sites fluctuated throughout its history and had approximately 400 stations from 1987 to 1992. The number of sites had declined to 140 sites in 1995, and in 1996 the network was reconfigured to cover 39 basins and included a broader range of parameters.

change from a water quality perspective has been lost. In comparison, the NASQAN provides an excellent source of material to evaluate and assess human impacts on the quality of the water.

11.5 Discussion

From the review of the selection criteria for hydrometric networks, it is evident that previous efforts in hydrometry tended to choose somewhat similar criteria. There is, however, a major distinction that could be made between efforts in hydrometry with those of the surface climate data efforts. It is evident in the work of Vose et al. (1992), Jones (1994), and GCOS (1998) that climate stations reflecting direct human contamination of data, such as the heat-island effect, are acceptable. In contrast, hydrologists have paid special attention in ensuring that the data from hydrometric sites were as free as possible from direct human interference on the landscape.

To assess the potential for human interference within hydrometric data as well as for assessing the accuracy of the measurements, local expert knowledge is required. The application of selection criteria without the participation of local experts having site specific knowledge will potentially result in specialised networks containing sites of dubious quality and worth. Analysis of such networks may lead to erroneous conclusions or hamper the identification of change attributable to climate change and variability.

An important aspect that should not be overlooked is the need to obtain visibility for the hydrological network for climate change detection within the scientific and policy communities. Efforts must be made to underline the importance of the specific stations that have been selected for inclusion in such specialised networks. Without suitable monitoring of potential change and support to its scientific analyses, it will be difficult if not impossible to ascertain the characterisation of change and the sufficiency of political measures taken to deal with the implications.

References

Alexander, RB., Slack, J.R, Ludtke, A.S., Fitzgerald, K & Schertz, T.L., 1998. Data from selected U.S. Geological Survey national stream water quality monitoring networks. Wat.

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Burn, D., 1994. Identification of a data collection network for detecting climatic change.

Canadian J. of Water Resources, 19(1), 27-38.

Environment Canada, 1996. Climate network rationalization. Atmospheric Environment Service, National Weather Services Directorate, Downsview, Ontario, November, 48p.

plus116 p. of annexes.

Environment Canada, 1999. Establishment of the Reference Hydrometric Basin Network (RHBN) for Canada — Draft. National Weather Services Directorate, Downsview, Ontario, January21, 1999, 42 p.

Global Climate Observing System (GCOS), 1998. Report on the adequacy of the global climate observing systems. COP4, GCOS-48, Buenos Aires, Argentina, November 2-23, 34 p.

Jones, P.D., 1994. Hemispheric surface air temperature variations: a reanalysis and an update to 1993. J. of Climate, 7, 1794-1802.

Lawford, R.G., 1992. Hydrological indicators of climate change: issue or opportunity? In:

Proceedings of the NHRI Workshop, No. 8, Using Hydrometric Data to Detect and Monitor Climatic Change, Environment Canada, NHRI, Saskatoon, Saskatchewan, 247 p.

Langbein, W.B. & Slack, J.R, 1982. Yearly variations in runoff and frequency of dry and wet years for the conterminous United States. 1911-79, U.S. Geological Survey Open File Report No. 82-751.

Peterson, T, Daan, H. & Jones, P., 1997. Initial selection of a GCOS suthce network. GCOS 34, WMO/TD No. 799, 14 p.

Pion, P.J., Winkler, T., Harvey, K.D. & Kimmett, DJt, 1991. Hydrometric data in support of climate change studies in Canada, presented at the NATO Advanced Research Workshop on Opportunities for Hydrological Data in Support of Climate Change Studies, Lahnstein, Germany, 26-30 August.

Slack, J.R. & Landwehr, J.M., 1992. Hydro-climatic data network (HCDN): a U.S.

Geological Survey streamflow data set for the United States for the study of climate variations. 1874-1988, U.S. Geological Survey Open File Report 92-129, USGS Water Supply Paper No. 2406, Reston, Virginia, 171 p.

Vose, R.S., Schmoyer, RL., Steurer, P.M., Peterson, T.C., Heim, R, Karl, T.R. & Eischeid, J., 1992. The global historical climatology network: long-term monthly temperature, precipitation, sea level pressure, and station pressure data. ORNL/CDIAC-53, NDP-041, Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, Oak Ridge, Tennessee.

Wallis, J.R., Lettenmaier, D.P. & Wood, E.F., 1991. A daily hydroclimatological data set for the continental United States. Wat. Resour. Res., 27(7), 1657-1663.

World Meteorological Organization (WMO) (Mitchell, Jr., J.M., Dzerdzeevskii, B., Flohn, H., Hofmeyr, W.L., Lamb, H.H., Rao, K.N. & Wallen, C.C.), 1966. Climate change, WMO - No. 195. TP. 100, Technical Note No. 79, 79 p.

World Meteorological Organization (WMO), 1986. Guidelines on the selection of re1 climatological stations (RCSs) from the existing climatological station network. WCP-1 16, WMOTTD-No. 130, 18 p.

World Meteorological Organization (WMO), 1988. Technical regulations. WMO - No. 49, Chapter D.l - Operational Hydrology, p. D.1.1, 1-3.

World Meteorological Organization (WMO), 1993. Report of the experts meeting on reièrence climatological stations (RCS) and national climate data catalogues (NCC).

WCDMP-No. 23, WMO -11) No. 535, Offenbach am Main, 25-27 August 1992, l4p. plus 94 p. of annexes.

CHAPTER 12

PHASE RANDOMISATION FOR CHANGE DETECTION