About Us | Help Videos | Contact Us | Subscriptions



This article in JEQ

  1. Vol. 27 No. 4, p. 923-935
    Received: Mar 3, 1997

    * Corresponding author(s): dmamatya@eos.ncsu.edu
Request Permissions


Effects of Controlled Drainage on Forest Water Quality

  1. D. M. Amatya *,
  2. J. W. Gilliam,
  3. R. W. Skaggs,
  4. M. E. Lebo and
  5. R. G. Campbell
  1. Biological and Agric. Engineering Dep., North Carolina State Univ., Raleigh, NC 27695-7625;
    Soil Science Dep., North Carolina State Univ., Raleigh, NC 27695-7619;
    Weyerhaeuser Co., New Bern, NC 28563-1391.



The effects of controlled drainage (CD) on hydrology and water quality are presented for three eastern North Carolina watersheds in loblolly pine (Pinus taeda L.). Timing of CD treatments were: the spring fish recruitment period in the downstream estuary in one watershed, and the summer-fall period to facilitate tree growth in another watershed. A third watershed was maintained under conventional drainage throughout the study. It was demonstrated that seasonal controlled drainage can reduce both the total drainage outflows and corresponding sediment and nutrient exports. For example, CD reduced drainage outflows by as much as 88% during the summer-fall and 39% during the spring with annual average reduction of 20 to 25%. Annual average total phosphorus (TP) and ammonium-nitrogen (NH4-N) exports from watersheds under treatment were reduced by 7 to 72% as compared to the watershed under conventional drainage. For other nutrients and total suspended solids (TSS), concentrations were significantly different (α = 0.05) among the three watersheds during the winter when they were all under conventional drainage. This indicated characteristic differences unrelated to applied treatments. Taking these differences into account, the reductions in annual average export of TSS (up to 47%) and nitrate plus nitrite-nitrogen (NO3+NO2-N) (up to 16%), total Kjeldahl nitrogen (TKN) (up to 45%) and total organic carbon (TOC) (up to 33%) from watersheds under treatment were directly attributed to reduction in outflows. Even though CD appeared to have increased concentrations of some of the nutrients analyzed, except for NH4-N, the applied treatments lowered the export of TSS and most nutrients measured. It is concluded that CD can be used to reduce TSS and nutrient exports from pine plantations, primarily through reduced drainage outflows.

Publication no. BAE97-06 of Biological and Agric. Engineering Dep., North Carolina State Univ., Raleigh, NC 27695-7625. This work was made possible by the financial support of the USDA-CSRS and the National Council of the Paper Industry for Air and Stream Improvement, Inc. (NCASI).

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

Copyright © .