Skip to main content


Buy Article:

$9.50 plus tax (Refund Policy)

Or sign up for a free trial

A wide variety of approaches have been proposed and utilized to quantify the pollutant load flowing past a fixed point on a stream. Obtaining satisfactory results from mass load estimators require adequate sampling strategies. Developing an adequate sampling and mass load estimation method appropriate for a given stream and a given constituent has been stated to be difficult, due to inconsistencies arising from both hydrologic and constituent characteristics. Systematic sampling supplemented by storm chasing has been reported to be the most effective strategy for estimating annual loads, but the approach could still result in load overestimations of 25–50%. Systematic sampling with little or no storm chasing is often the strategy of choice due to budgetary and manpower constraints.

The objective of this study was to determine if storm chasing is necessary in making mass load estimations in small karst basins. “True” nitrate-nitrogen and total solute mass loads were determined from continuously collected data and compared with mass loads determined from two systematic sampling techniques. The first method (method A) utilized weekly, biweekly, and monthly grab sampling in conjunction with instantaneous flow measurements. The second (method B) consisted of weekly, biweekly, and monthly grab sampling with continuous flow measurement (10-minute intervals). Continuous flow data was integrated to obtain the total flow volume represented by each grab sample.

A comparison of “true” loads with loads produced by each of the techniques revealed that within this basin, storm chasing was not necessary. All percent differences between load estimates and the true load were less than 20%. Method B was generally superior to method A in estimating mass loads. Method B consistently yielded percent differences less than 10% and often less than 5%. Monthly grab sampling with continuous flow measurement produced satisfactory mass load estimations without the expense and effort of storm chasing. Method A produced very satisfactory results with biweekly sampling and instantaneous flow measurement. Storm sampling is not required because it was found that the flowcomposited storm nitrate-N and total solute sample concentrations were comparable to the systematically collected grab sample concentrations both in value and trend.
No Reference information available - sign in for access.
No Citation information available - sign in for access.
No Supplementary Data.
No Article Media
No Metrics

Document Type: Research Article

Publication date: 2003-01-01

More about this publication?
  • Proceedings of the Water Environment Federation is an archive of papers published in the proceedings of the annual Water Environment Federation® Technical Exhibition and Conference (WEFTEC® ) and specialty conferences held since the year 2000. These proceedings are not peer reviewed.

    A subscription to the Proceedings of the Water Environment Federation includes access to most papers presented at the annual WEF Technical Exhibition and Conference (WEFTEC) and other conferences held since 2000. Subscription access begins 12 months after the event and is valid for 12 months from month of purchase. A subscription to the Proceedings of the Water Environment Federation is included in Water Environment Federation (WEF) membership.

    WEF Members: Sign in (right panel) with your IngentaConnect user name and password to receive complimentary access. Access begins 12 months after the conference or event
  • Subscribe to this Title
  • Membership Information
  • About WEF Proceedings
  • WEFTEC Conference Information
  • Learn about the many other WEF member benefits and join today
  • Ingenta Connect is not responsible for the content or availability of external websites
  • Access Key
  • Free content
  • Partial Free content
  • New content
  • Open access content
  • Partial Open access content
  • Subscribed content
  • Partial Subscribed content
  • Free trial content
Cookie Policy
Cookie Policy
Ingenta Connect website makes use of cookies so as to keep track of data that you have filled in. I am Happy with this Find out more