You are here:
THE MAGIC SIMULATION OF SURFACE WATER ACIDIFICATION AT, AND FIRST YEAR RESULTS FROM, BEAR BROOK WATERSHED MANIPULATION, MAINE, USA
Citation:
Norton, S., R. Wright, J. Kahl, AND J. Scofield. THE MAGIC SIMULATION OF SURFACE WATER ACIDIFICATION AT, AND FIRST YEAR RESULTS FROM, BEAR BROOK WATERSHED MANIPULATION, MAINE, USA. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/J-92/400 (NTIS PB93121291).
Description:
The catchments of East and West Bear Brooks, Maine, USA, with similar stream chemistries and hydrographs, have been hydrologically and chemically monitored for 3.5 years. hese clear water streams are low in ANC (0-70 ueq litre-1), with variations caused by changing concentrations of base cations, SO4, NO3 and C1. he latter range between 90-120, 0-40 and 65-75 ueq litre-1 respectively. he West Bear catchment is being treated with six applications per year of dry (NH4)2SO4 at 1800 eq ha-1 year-1. fter one year of treatment, the response of the stream chemistry and the response modelled by MAGIC are similar. etentions of NH4 and SO4 are nearly 100% and greater than 80% respectively. he additoinal flux of SO4 is compensated principally by an increased Ca concentration. pisodes of high discharge in the treated catchment are now characterized by lower ANC and pH, and higher A1 than prior to the manipulation. oncentrations of NO3 have increased about 10 ueq litre-1 during the dormant season, presumably due to additional nitrification of N and NH4. ischarge-chemistry relationships indicate that changes in stream chemistry, except for NO3, are dominated by ion exchange reactions in the upper part of the soil profile.