Analysis of suspended sediment dynamics at event scale: comparison between a Mediterranean and an Alpine basin

Figures & data

Figure 1. (a) The Carapelle catchment and (b) the Rio Cordon catchment, in Italy.

Table 1. Variables and units associated to the single hydrological events.

Flow event conditions
Qp (m^3 s^−^1)	Water discharge peak
Qm (m^3 s^−1)	Mean water discharge of the flow event
Qi (m^3 s^−1)	Initial water discharge of the flow event
QSSC (m^3 s^−1)	Water discharge when SSCp takes place
Ru (10^3 m^3)	Total runoff of the flow event
SSCp (g L^−^1)	Suspended sediment concentration peak
SSCm (g L^−1)	Mean suspended sediment concentration of the flow event
SSCQ (g L^−1)	Suspended concentration when Qp takes place
TSS (t)	Total sediment yield
Ptot (mm)	Total rainfall that causes the flow event
Imax (mm h^−^1)	Maximum hourly rainfall intensity in 1 hour range
Iav (mm h^−^1)	Average hourly rainfall intensity
∆t (h)	Time lag between Qp and SSCp
∆t(BSSC–BQ) (h)	Time lag between sedigraph barycentre and hydrograph barycentre
∆t(BQ–BP) (h)	Time lag between hydrograph barycentre and pluviograph barycentre
∆t(BSSC–BP) (h)	Time lag between sedigraph barycentre and pluviograph barycentre
Antecedent flow event conditions
Qa1d (m^3 s^−1)	Mean water discharge during the 24 h before the flow event
P3, P6, P12, P24, P48 (mm)	Total rainfall during 3, 6, 12, 24 and 48 h before the rainfall that causes the flow event

Figure 2. Graphical explanation of the studied variables. The acronyms of the variables are explained in Table 1.

Table 2. Descriptive statistics resulting from the analyses of the single hydrological events and associated variables (see Table 1). A total of 41 and 30 single floods were recorded, respectively, in the Carapelle and Rio Cordon watersheds. Min: minimum; Max: maximum; SD: standard deviation.

	Carapelle				Rio Cordon
	Min	Max	Mean	SD	Min	Max	Mean	SD
Qp	3.22	159.50	32.64	30.77	0.83	10.42	2.27	1.83
Qm	1.94	40.16	12.83	9.02	0.44	2.60	1.28	0.55
Qi	0.57	15.00	4.46	3.83	0.16	1.40	0.70	0.29
QSSC	0.64	111.50	25.79	25.82	0.72	9.31	1.90	1.57
Ru	160.47	10 336.18	1557.14	1856.91	1.42	538.67	113.32	155.81
SSCp	1.11	62.94	18.38	15.51	0.01	57.89	4.64	10.81
SSCm	0.69	25.32	6.16	5.37	0.00	8.46	0.85	1.90
SSCQ	0.18	42.34	9.31	10.38	0.00	48.90	3.40	9.31
TSS	153.0	187259.0	16 633.0	33 335.0	0.00	1060.0	69.0	196.0
Ptot	3.10	58.8	15.30	12.93	5.00	198.50	55.90	47.05
Imax	0.70	8.90	3.40	1.82	1.70	32.60	11.50	6.71
Iav	0.30	2.90	1.10	0.62	0.40	16.00	3.60	2.96
∆t	−3.50	12.50	3.00	3.51	−17.00	0.50	−2.19	4.34
∆t(BSSC–BQ)	−5.03	5.23	0.12	2.14	−30.41	5.53	−5.51	8.91
∆t(BQ–BP)	5.93	41.04	16.76	7.00	−0.79	36.28	9.55	10.14
∆t(BSSC–BP)	5.56	36.91	16.88	6.58	−18.23	25.08	4.04	9.11
Qa1d	0.52	18.19	5.14	4.81	-	-	-	-
P3	0.00	0.60	0.07	0.14	0.00	24.60	6.62	6.80
P6	0.00	1.88	0.16	0.34	0.00	39.20	10.38	10.46
P12	0.00	16.49	1.52	3.67	0.00	86.00	19.26	20.13
P24	0.00	20.21	3.23	5.06	0.00	78.00	29.53	24.97
P48	0.00	32.21	7.51	8.81	0.00	106.20	35.87	29.25

Table 3. Correlation matrix for the parameters analyzed in the forty-one Carapelle events (see Table 1). The coefficients in bold are significant p-value < 0.01.

	Qp	Qm	Qi	QSSC	Ru	SSCp	SSCm	SSCQ	TSS	Ptot	Imax	Iav	∆t	∆t (BSSC–BQ)	∆t (BQ–BP)	∆t (BSSC–BP)	Qa1d	P3	P6	P12	P24	P48
Qp	1
Qm	0.864	1
Qi	0.090	0.398	1
QSSC	0.979	0.922	0.144	1
Ru	0.826	0.784	0.183	0.843	1
SSCp	0.459	0.421	0.025	0.457	0.291	1
SSCm	0.271	0.385	0.186	0.300	0.094	0.883	1
SSCQ	0.791	0.786	0.108	0.806	0.667	0.737	0.625	1
TSS	0.852	0.762	0.161	0.839	0.916	0.477	0.306	0.798	1
Ptot	0.581	0.458	–0.210	0.597	0.660	0.270	0.020	0.444	0.587	1
Imax	0.338	0.214	–0.290	0.327	0.165	0.362	0.210	0.281	0.246	0.583	1
Iav	0.292	0.140	–0.337	0.260	0.065	0.472	0.332	0.365	0.239	0.411	0.829	1
∆t	–0.669	–0.711	–0.119	–0.737	–0.543	–0.454	–0.342	–0.653	–0.464	–0.441	–0.078	0.038	1
∆t(BSSC-BQ)	–0.341	–0.368	–0.171	–0.348	–0.567	–0.203	0.043	–0.304	–0.405	–0.461	–0.174	–0.026	0.310	1
∆t(BQ-BP)	–0.284	–0.382	–0.294	–0.310	–0.058	–0.365	–0.457	–0.390	–0.217	0.285	0.183	0.005	0.338	–0.346	1
∆t(BSSC-BP)	–0.413	–0.526	–0.369	–0.443	–0.246	–0.454	–0.472	–0.514	–0.363	0.154	0.138	–0.003	0.460	–0.044	0.952	1
Qa1d	0.157	0.421	0.886	0.211	0.314	–0.104	0.001	0.099	0.273	–0.172	–0.348	–0.388	–0.125	–0.205	–0.325	–0.413	1
P3	–0.002	–0.044	0.197	–0.024	–0.037	0.245	0.297	0.148	0.054	–0.034	0.018	0.001	0.061	0.091	–0.098	–0.075	0.031	1
P6	0.002	0.048	0.387	–0.006	–0.055	0.350	0.472	0.217	0.052	–0.078	–0.033	–0.019	–0.003	0.094	–0.156	–0.135	0.165	0.919	1
P12	0.048	0.222	0.538	0.088	–0.034	0.026	0.158	0.044	–0.027	–0.140	–0.084	–0.143	–0.155	0.028	–0.244	–0.251	0.503	0.269	0.378	1
P24	0.081	0.252	0.620	0.124	0.063	0.144	0.298	0.159	0.127	–0.074	–0.109	–0.200	–0.169	0.025	–0.243	–0.251	0.602	0.453	0.593	0.858	1
P48	0.087	0.192	0.496	0.098	0.102	0.077	0.192	0.075	0.174	–0.121	–0.121	–0.178	–0.086	0.028	–0.341	–0.354	0.654	0.113	0.236	0.405	0.596	1

Figure 3. Comparison between the time lags of water discharge peak–suspended sediment concentration peak (∆t) and the corresponding time delays between sedigraph and hydrograph barycentres, ∆t(BSSC–BQ), recorded in the Carapelle and Rio Cordon catchments.

Table 4. Correlation matrix for the parameters analyzed in the thirty Rio Cordon events (see Table 1). The coefficients in bold are significant p-value < 0.01.

	Qp	Qm	Qi	QSSC	Ru	SSCp	SSCm	SSCQ	TSS	Ptot	Imax	Iav	∆t	∆t (BSSC-BQ)	∆t (BQ-BP)	∆t (BSSC-BP)	P3	P6	P12	P24	P48
Qp	1
Qm	0.718	1
Qi	0.197	0.518	1
QSSC	0.913	0.698	0.288	1
Ru	0.381	0.560	–0.042	0.146	1
SSCp	0.859	0.515	0.122	0.911	0.184	1
SSCm	0.530	0.499	0.002	0.602	0.385	0.669	1
SSCQ	0.817	0.480	0.090	0.905	0.111	0.983	0.685	1
TSS	0.902	0.564	0.145	0.894	0.244	0.973	0.666	0.947	1
Ptot	0.153	0.460	–0.077	0.184	0.649	0.201	0.449	0.181	0.153	1
Imax	0.555	0.298	0.077	0.701	–0.142	0.595	0.357	0.614	0.535	0.109	1
Iav	0.637	0.412	0.343	0.752	–0.220	0.672	0.342	0.682	0.689	–0.063	0.753	1
∆t	0.105	0.085	0.123	0.205	–0.110	0.096	0.140	0.150	0.076	–0.045	0.261	0.283	1
∆t(BSSC-BQ)	–0.194	–0.366	–0.006	–0.055	–0.767	–0.117	–0.384	–0.090	–0.120	–0.697	0.064	0.193	0.034	1
∆t(BQ-BP)	0.074	0.117	–0.082	–0.166	0.415	–0.079	–0.025	–0.112	–0.028	0.258	–0.287	–0.260	–0.357	–0.549	1
∆t(BSSC-BP)	–0.108	–0.228	–0.097	–0.238	–0.288	–0.203	–0.403	–0.213	–0.148	–0.394	–0.258	–0.101	–0.364	0.367	0.576	1
P3	0.139	0.076	0.101	0.148	0.120	0.284	0.238	0.324	0.258	0.312	0.132	0.254	0.195	–0.511	0.371	–0.087	1
P6	0.082	0.087	0.096	0.082	0.236	0.243	0.212	0.278	0.203	0.411	0.049	0.105	0.051	–0.557	0.346	–0.159	0.895	1
P12	–0.019	0.144	–0.046	0.007	0.344	0.038	0.193	0.061	0.025	0.631	–0.049	–0.152	0.052	–0.519	0.279	–0.197	0.437	0.546	1
P24	0.141	0.216	0.065	0.166	0.246	0.215	0.306	0.240	0.245	0.454	–0.086	–0.036	0.044	–0.328	0.216	–0.080	0.352	0.438	0.849	1
P48	0.090	0.129	–0.025	0.083	0.218	0.138	0.241	0.163	0.176	0.401	–0.154	–0.099	0.023	–0.267	0.281	0.051	0.291	0.347	0.812	0.961	1

Figure 4. PCA for (a) the Carapelle catchment and (b) the Rio Cordon catchment. Component plot in rotated space. The variables are described in Table 1.

Figure 5. Event distributions in the factorial planes according to hysteresis directions and hysteresis shape in (a, b) the Carapelle catchment and (c, d) the Rio Cordon catchment.