About Us | Help Videos | Contact Us | Subscriptions
 

Abstract

 

This article in JEQ

  1. Vol. 32 No. 6, p. 2290-2300
     
    Received: Aug 7, 2002


    * Corresponding author(s): lars.rapp@md.slu.se
 View
 Download
 Alerts
 Permissions
 Share

doi:10.2134/jeq2003.2290

Modeling Surface Water Critical Loads with PROFILE

  1. L. Rapp * and
  2. K. Bishop
  1. Department of Environmental Assessment, Swedish University of Agricultural Sciences, SE-750 07 Uppsala, Sweden

Abstract

The critical load concept has become a valuable tool for policymakers in the European negotiations on emission reductions. Despite the international acceptance, ongoing validation of critical load methodology is of the utmost importance to avoid a situation where the calculation results are difficult to defend. In this paper we explore the potential of using the steady state soil chemistry model PROFILE as an alternative to the Steady State Water Chemistry (SSWC) method for calculating critical loads of acidity. The hypothesis is that the uncertainty in prediction of preindustrial leaching of base cations is reduced when soil properties instead of lake chemistry are used as input data. Paleolimnological reconstructions of preindustrial lake chemistry are used to test PROFILE. As PROFILE requires soil data that are not generally available on a catchment level, we used distributions of crucial parameters from soil survey data within the vicinity of five lakes for which paleoecological pH reconstructions were available. An important concern is the characterization of catchment hydrology. A calibration of the “effective” soil depth, needed to give PROFILE predictions that coincided with paleolimnology, suggested that approximately 0.6 m of the total soil depth was hydrologically active in supplying acid neutralizing capacity (ANC) to runoff through weathering. At present, there is insufficient evidence to either recommend or reject the PROFILE model for surface water critical loads. Before such a judgement can be made, the approach presented here has to be tested for other regions, and the definition of catchment hydrology needs to be investigated further.

  Please view the pdf by using the Full Text (PDF) link under 'View' to the left.

Copyright © 2003. American Society of Agronomy, Crop Science Society of America, Soil Science SocietyASA, CSSA, SSSA