Table 11. Changes in peat thickness and nutrient content in soil cores collected from Wood River Wetland, upper Klamath River basin, Oregon.

[Data from Snyder and Morace (1997, p. 39) and D.T. Snyder (U.S. Geological Survey, unpub. data, 1997). Shading indicates cores closest to the ground-water piezometer nests. Initial: prior to the beginning of drainage of a wetland for agricultural use. 1995: quantity present in the year 1995, the year of core sample acquisition. Loss: the difference between initial and 1995. See Snyder and Morace (1997, p. 21–24) for method of calculation. Abbreviations: NU, North Unit; SU, South Unit; WRR, Wood River Ranch; ft, foot; kg, kilogram]

Wetland unit	Core name	Area of wetland represented by core (acres)	Peat thickness				Peat mass					Total organic carbon mass
			Initial (ft)	1995 (ft)	Loss (ft)		Initial (kg)	1995 (kg)	Loss (kg)	Loss (percent)		Initial (kg)	1995 (kg)	Loss (kg)	Loss (percent)
North Unit	WRR-05	343	4.3	3.5	0.8		220,000,000	210,000,000	12,000,000	5		84,000,000	70,000,000	14,000,000	17
	WRR-07	223	0.7	0.3	0.4		25,000,000	23,000,000	2,000,000	8		8,300,000	4,000,000	4,200,000	51
	WRR-08	491	11.3	7.3	4.0		900,000,000	730,000,000	170,000,000	19		290,000,000	100,000,000	190,000,000	65
	WRR-03	421	10.1	10.1	0		840,000,000	840,000,000	0	0		230,000,000	230,000,000	0	0
	WRR-04	165	10.7	10.0	0.7		290,000,000	290,000,000	74,000,000	3		100,000,000	92,000,000	7,700,000	8
South Unit	WRR-01	225	2.5	1.2	1.3		90,000,000	71,000,000	19,000,000	21		30,000,000	13,000,000	16,000,000	56
	WRR-02	187	7.0	3.7	3.3		210,000,000	180,000,000	34,000,000	16		69,000,000	32,000,000	37,000,000	53
	WRR-10	390	8.5	5.5	3.0		500,000,000	430,000,000	74,000,000	15		160,000,000	90,000,000	70,000,000	44
	WRR-09	225	14.5	10.1	4.4		520,000,000	480,000,000	36,000,000	7		160,000,000	110,000,000	53,000,000	33
	Sum	2,670				3,600,000,000	3,200,000,000	360,000,000		1,100,000,000	750,000,000	390,000,000
	Average	297	7.7	5.7	2.0	400,000,000	360,000,000	40,000,000	10	130,000,000	83,000,000	44,000,000	36
	NU average	329	7.4	6.2	1.2	460,000,000	420,000,000	39,000,000	7	140,000,000	100,000,000	43,000,000	28
	SU average	257	8.1	5.1	3.0	330,000,000	290,000,000	41,000,000	15	100,000,000	61,000,000	44,000,000	46

Wetland unit	Core name	Area of wetland represented by core (acres)	Total nitrogen mass					Total phosphorus mass
			Initial (kg)	1995 (kg)	Loss (kg)	Loss (percent)		Initial (kg)	1995 (kg)	Loss (kg)	Loss (percent)
North Unit	WRR-05	343	4,900,000	4,000,000	870,000	18		130,000	120,000	800	1
	WRR-07	223	590,000	390,000	200,000	34		17,000	17,000	0	0
	WRR-08	491	21,000,000	10,000,000	10,000,000	50		550,000	280,000	270,000	49
	WRR-03	421	19,000,000	19,000,000	0	0		350,000	350,000	0	0
	WRR-04	165	4,900,000	4,400,000	500,000	10		140,000	120,000	13,000	10
South Unit	WRR-01	225	2,100,000	1,000,000	1,100,000	51		56,000	54,000	1,500	3
	WRR-02	187	4,900,000	2,700,000	2,200,000	45		130,000	81,000	53,000	39
	WRR-10	390	12,000,000	6,800,000	4,800,000	42		250,000	180,000	76,000	30
	WRR-09	225	11,000,000	7,900,000	3,400,000	30		270,000	190,000	73,000	28
	Sum	2,670	79,000,000	56,000,000	23,000,000		1,900,000	1,400,000	480,000
	Average	297	8,800,000	6,200,000	2,600,000	31	210,000	160,000	54,000	18
	NU average	329	9,900,000	7,500,000	2,400,000	23	230,000	180,000	56,000	12
	SU average	257	7,500,000	4,600,000	2,900,000	42	180,000	130,000	51,000	25