EFFECTS OF CONTROLLED DRAINAGE ON STORM EVENT HYDROLOGY IN A LOBLOLLY PINE PLANTATION¹

Abstract

A paired watershed approach was utilized to study the effects of three water management regimes on storm event hydrology in three experimental watersheds in a drained loblolly pine (Pinus taeda L.) plantation in eastern North Carolina. The regimes were: (1) conventional drainage, (2) controlled drainage (CD) to reduce outflows during spring fish recruitment, and (3) controlled drainage to reduce outflows and conserve water during the growing season. Data from two pit-treatment years and three years of CD treatment with raised weirs at the watershed outlet are presented. CD treatment resulted in rises in water table elevations during the summer. But the rises were small and short-lived due to increased evapotranspiration (ET) rates as compared to the spring treatment with lower ET demands. CD treatment had no effect on water tables deeper than 1.3 m. CD treatments, however, significantly (a = 0.05) reduced the stonn outflows for all events, and peak outflow rates for most of the events depending upon the outlet weir level. In some events, flows did not occur at all in watersheds with CD. When event outflows occurred, duration of the event was sharply reduced because of reduced effective ditch depth. Water table depth at the start of an event influenced the effect of CD treatment on storm event hydrology.(KEY TERMS: controlled drainage; loblolly pine; water table; drainage outflow; event hydrograph.)1Paper No.

Impacts of drainage water management on subsurface drain flow, nitrate concentration, and nitrate loads in Indiana

“…As outlined by Clausen and Spooner (1993), the paired field statistical method uses linear regression from the calibration period (periods with no control) to establish the pretreatment relationship between fields, followed by an analysis of covariance of the treatment data (periods with one field managed) to determine the differences between the calibration and treatment periods. For this study, periods when the drainage outlets were lowered for field operations were also used for calibration information, similar to a controlled surface drainage study by Amatya et al (2000). The periods immediately after the drainage outlets were lowered, until flow in the managed field decreased to the flow in the free-draining field (8 to 13 days in spring; 0 to 10 days in the fall), were not included in the treatment period analysis.…”

Consistency of Hydrologic Relationships of a Paired Watershed Approach

“…A statistically significant relationship between the control and treatment watersheds is established during calibration period such that any significant shift detected in the relationship during treatment is attributed to the treatment effects. The approach has been extended to other fields of study to assess effectiveness of conser-vation practices [13][14][15]; agroforestry [16][17][18][19][20]; nitrogen and phosphorus management [21,22]; riparian restoration [23]; controlled drainage [24][25][26]; and land development [27].…”

Curve Number Derivation for Watersheds Draining Two Headwater Streams in Lower Coastal Plain South Carolina, USA

“…The vertical distribution of storm events of similar rainfall amounts is evident when compared between both watersheds. This comparable distribution is indicative of the large range in runoff generation that has been observed on these LCP headwater streams for similar rainfall amounts at different locations (Eshleman et al ., ; Amatya et al ., , ; Slattery et al ., ; Harder et al ., ; La Torre Torres et al ., ). For UDC, the CN‐II that represents the drained condition has been included to demonstrate that it is a poor estimate for the CN at this site (Figure ).…”