Newman Lake restoration: A case study. Part I. Chemical and biological responses to phosphorus control

Figures & data

Figure 1 Bathymetric map of Newman Lake, Washington showing major stream and sample site locations. Depth contours are in feet (after Wolcott 1964).

Figure 2 Total phosphorus concentrations in Thompson Creek, Newman Lake watershed, WA. Y-axis values are in μg-P/L. Circles = annual median TP concentrations; shaded boxes = 95% confidence intervals. Median TP for data up to 2002 is 47 μg-P/L.

Figure 3 Average annual volume-weighted total phosphorus in Newman Lake. Y-axis values are in μg-P/L. 1989 = whole lake alum treatment; 1992 = hypolimnetic oxygenation installed; 1997 = 100-yr flood event; 1997 = microfloc alum installed; 2000 = oxygenation and alum systems out of service (see text for details).

Figure 4 Box plots of annual volume-weighted total phosphorus concentrations in Newman Lake, grouped by treatment intervals. Y-axis values are in μg-P/L. Squares = median values; shaded boxes = inner quartiles, including data +/- 25% of medians; whiskers = minimum/maximum lines. (a) Annual volume-weighted, whole-lake TP for all stations and all depths (n = 1420). (b) Annual volume-weighted epilimnion TP (n = 475). (c) Annual volume-weighted metalimnion TP (n = 472). (d) Annual volume-weighted hypolimnion TP (n = 473).

Figure 5 Frequency histograms for volume-weighted TP in Newman Lake. Y-axis in percentages of total observations; X-axis in μg-TP/L. (A) Cumulative post-restoration data range frequencies (n = 1345) compared to pre-restoration frequencies (n = 176). (B) Histograms for data stratified into pre-oxygenation years (pre-1992, n = 286), years with partial oxygenation (1992–1996, n = 455), and years with full oxygenation (1997–1999 and 2001–2007, n = 780). (C) Histograms for data stratified into pre-oxygenation years (pre-1992, n = 286), and years operated with full oxygenation within the designed system environmental parameters (2001–2007, n = 780) (see text for details).

Table 1 Total phosphorus nutrient budget, loading rates and coefficients for Newman Lake, calculated for all years in which sufficient inlet and outlet monitoring data are available. Min Gross = minimum gross yearly total phosphorus load calculated as the sum of all positive loads. Net internal = arithmatic sum of all positive and negative loads. Ltot = total yearly phosphorus load divided by watershed and lake areas. Lext = total annual load from inlets divided by lake area. Robs and Rpred are observed and predicted phosphorus retention coefficients, respectively (see Nurnberg 1984 and text for details). qs = annual areal water load. Anoxic factor is calculated per Nurnberg (1987). Summer values are for the four month period, inclusive of June through September, and summer rates are extrapolated to an annual basis. For 2004 and 2005, rates are extrapolated to an annual basis.

	Total	Min gross	Net	Min gross	L tot	L tot	Anoxic	L ext				L int
	inlets	internal	internal	total**	watershed	lake	factor	lake		qs		mg/m^2/
	kg	kg	kg	kg	mg/m^2/yr	mg/m^2/yr	days/yr	mg/m^2/yr	R obs	m/yr	R pred	yr
1985/1986 Water Yr	544	2,596	706	3,140	43.0	610	57	106	0.39	2.96	0.72	34
Summer 1986	85	942	762	1,027	42.1	598
Note: pre-restoration
Total 1990	1,037	485	−724	1,522	20.8	296	56	201	0.57	2.66	0.73	31
Summer 1990	235	47	−552	283	11.6	165
Note: year following September 1989 whole lake alum treatment
Total 2004	461	711	−283	1,173	16.0	228	6	90	0.62	2.35	0.74	11
Summer 2004	85	24	−487	109	4.5	63
Note: oxygenation and microfloc operational
Total 2005 (10 month)	186	539	−351	725	11.9	169	2	48	0.79	1.51	0.77	−1
Summer 2005	19	293	−395	312	12.8	181
Note: oxygenation and microfloc operational, low flow year
Total 2006 (10 month)	1,128	287	−724	1,415	23.2	330	10	263	0.90	4.02	0.68	−58
Summer 2006	45	59	−266	104	4.3	60
Note: oxygenation and microfloc operational, high flow year

Figure 6 Maximum total and cyanobacteria biovolumes in Newman Lake from 1989 through 2007. Maxima are highest observed for each year and are not necessarily concurrent. Y-axis phytoplankton biovolumes are in cm³/m³.

Table 2a Average growing season (April through October), photic zone algae biomass in Newman Lake for all available data years, 1986 to 2008. Values are in m³/lake. For 1986, data are available only from July through October.

	1986	1990	1991	1992	1999	2000	2001	2002	2004	2005	2006	2007	2008
Chlorophyta	3	1	5	10	1	3	1	14	3	6	2	2	1
Pyrrhophyta	0	10	5	11	11	5	2	1	1	5	8	6	7
Chrysophyta	0	0	11	0	1	11	15	8	3	1	2	5	1
Bacillariophyta	39	64	60	71	39	32	49	39	33	36	16	16	11
Cyanophyta	9	32	18	12	10	4	0	0	3	1	1	1	1
All Phyla Totals	51	107	99	103	63	57	68	62	44	50	29	32	23

Table 2b Average growing season (April through October), photic zone algae biomass in Newman Lake for all available data years, 1986 to 2008. Values expressed as percent of total phytoplankton biomass.

	1986	1990	1991	1992	1999	2000	2001	2002	2004	2005	2006	2007	2008
Chlorophyta	5	1	5	9	1	6	2	22	8	13	5	7	3
Pyrrhophyta	0	10	5	11	17	9	3	1	2	11	27	19	23
Chrysophyta	0	0	11	0	2	19	22	13	7	2	8	15
Bacillariophyta	76	60	61	69	61	56	72	63	75	72	57	52	36
Cyanophyta	18	29	19	11	16	8	0	0	8	2	3	2	2

Wolcott , E. E. 1964 . Lakes of Washington. Vol. II Eastern Washington , Olympia , WA : Dept. of Conservation, Division of Water Resources . Water Supply Bulletin No. 14

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