Wbuytaert at 21:56, 3 August 2008

2008-08-03T21:56:06Z

Wbuytaert at 03:36, 9 May 2008

2008-05-09T03:36:57Z

New page

nothing in here yet :(

← Older revision		Revision as of 21:56, 3 August 2008
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−	~~nothing~~ in ~~here~~ yet :(	+	==Introduction==
		+	Chapman (1999) gives an excellent overview of baseflow separation techniques. Recursive digital filters are easiest to automate. Below are a few R implementations of the filter equations listed on the site:
		+
		+	NOTE: this is work in progress - the scripts have not yet been thoroughly tested and may contain bugs!
		+
		+
		+	==Filter equations==
		+
		+	===One-parameter algorithm===
		+
		+	Chapman (1999) equation 8:
		+
		+	bf_oneparam <- function(discharge, k){
		+	bf <- rep(discharge[1],length(discharge))
		+	for(i in 2:length(discharge)) {
		+	bf[i] <- (kbf[i-1]/(2-k)) + ((1-k)discharge[i]/(2-k))
		+	if(bf[i] > discharge[i]) bf[i] <- discharge[i]
		+	}
		+	return(bf)
		+	}
		+
		+	Parameter k is the recession constant during periods without direct runoff.
		+
		+	===Boughton two-parameter algorithm===
		+
		+	Chapman (1999) equation 9:
		+
		+	bf_boughton <- function(discharge, k, C){
		+	bf <- rep(discharge[1],length(discharge))
		+	for(i in 2:length(discharge)) {
		+	bf[i] <- (kbf[i-1]/(1+C)) + (Cdischarge[i]/(1+C))
		+	if(bf[i] > discharge[i]) bf[i] <- discharge[i]
		+	}
		+	return(bf)
		+	}
		+
		+	===IHACRES three-parameter algorithm===
		+
		+	Chapman (1999) equation 11:
		+
		+	bf_IHACRES <- function(discharge, k, C, a){
		+	bf <- rep(discharge[1],length(discharge))
		+	for(i in 2:length(discharge)) {
		+	bf[i] <- (kbf[i-1]/(1+C)) + (C(discharge[i] + a*discharge[i-1])/(1+C))
		+	if(bf[i] > discharge[i]) bf[i] <- discharge[i]
		+	}
		+	return(bf)
		+	}
		+
		+	<!-- ===Lyne and Hollick algorithm===
		+
		+	===Chapman algorithm===
		+
		+	===Furey and Gupta filter=== -->
		+
		+
		+	==References==
		+
		+	* Chapman, T., 1999. A comparison of algorithms for stream flow recession and baseflow separation. Hydrol. Process. 13, 701-714

Baseflow separation - Revision history

Wbuytaert at 21:56, 3 August 2008

Wbuytaert at 03:36, 9 May 2008