Long term response of surface water ANC from 1850 to 2150. Forecast scenarios from 1991 to 2150 represent four alternative acid deposition scenarios.
Trossachs region of central Scotland
Under Scenario 1 the long-term recovery in stream water ANC does not approach simulated background levels despite reductions in non-marine S deposition of the order of c.50-60% at all sites. Predicted responses fall into two categories:
Sites showing long term deterioration under Scenario 1 and currently leaking N are predicted to recover under Scenario 2. Forecasts under Scenario 3 suggest that recovery is more pronounced , in terms of achieving background ANC, if all non-marine S is removed from deposition. Under Scenario 4, all sites recover towards background ANC but the return to background conditions is predicted to take several hundreds of years.