Table 3. Input variables for the ERI...

Table 3.

Input variables for the ERI

Variable	Description	Scale	Description	Application	Description	Calculation
AE_u	A. Active bank erosion beneath the crossing	0	No or unsatisfactory photographic evidence	AEL_u	A1. Erosion beneath the crossing, left bank	AE_u = max (AEL_u, AER_u)
		1	Absence of evidence of bank erosion	AER_u	A2. Erosion beneath the crossing, right bank
		3	Evidence of bank erosion
		5	Evidence of severe bank erosion
AE_5w	B. Active bank erosion five channel widths (5w) upstream or downstream of the crossing	0	No or unsatisfactory photographic evidence	AEUL_5w	B1. Erosion upstream of the crossing, left bank	AE_5w = max (AEUL_5w, AEUR_5w, AEDL_5w, AEDR_5w)
		1	Absence of evidence of bank erosion	AEUR_5w	B2. Erosion upstream of the crossing, right bank
		3	Evidence of bank erosion	AEDL_5w	B3. Erosion downstream of the crossing, left bank
		5	Evidence of severe bank erosion	AEDR_5w	B4. Erosion downstream of the crossing, right bank
BP_u	C1. Bank protection beneath the crossing	0	No or unsatisfactory photographic evidence	BPL_u	C1a. Bank protection beneath the crossing, left bank	BP_u = max (BPL_u, BPR_u)
		1	Hard structure (concrete/masonry/steel piles)	BPR_u	C1b. Bank protection beneath the crossing, right bank
		3	Soft structure (rip-rap, gabion basket, other)
		5	No protection
BP_5w	C2. Bank protection five channel widths upstream or downstream	0	No or unsatisfactory photographic evidence	BPUL_5w	C2a. Bank protection upstream of the crossing, left bank	BP_5w = max (BPUL_5w, BPUR_5w, BPDL_5w, BPDR_5w)
		1	Hard structure (concrete/masonry/steel piles)	BPUR_5w	C2b. Bank protection upstream of the crossing, right bank
		3	Soft structure (rip-rap, gabion basket, other)	BPDL_5w	C2c. Bank protection downstream of the crossing, left bank
		5	No protection	BPDR_5w	C2d. Bank protection downstream of the crossing, right bank
Condition	Condition of bank protection	1	Undamaged – intact as-new condition
		2	Minor damage – intact but with some isolated damage
		3	Moderate – intact but with widespread damage
		4	Severe damage – intact but likely to fail and remedial work required to stabilise bank
		5	Failed – in pieces, offers no protection
β	D. Bank angle	1	<30°
		3	30–80°
		5	>80°/undercut
V	E. Vegetation	1	Both high and low vegetation
		3	Either low or high vegetation
		5	No vegetation or very sparse cover

Variable	Description	Scale	Description	Application	Description	Calculation
AE_u	A. Active bank erosion beneath the crossing	0	No or unsatisfactory photographic evidence	AEL_u	A1. Erosion beneath the crossing, left bank	AE_u = max (AEL_u, AER_u)
		1	Absence of evidence of bank erosion	AER_u	A2. Erosion beneath the crossing, right bank
		3	Evidence of bank erosion
		5	Evidence of severe bank erosion
AE_5w	B. Active bank erosion five channel widths (5w) upstream or downstream of the crossing	0	No or unsatisfactory photographic evidence	AEUL_5w	B1. Erosion upstream of the crossing, left bank	AE_5w = max (AEUL_5w, AEUR_5w, AEDL_5w, AEDR_5w)
		1	Absence of evidence of bank erosion	AEUR_5w	B2. Erosion upstream of the crossing, right bank
		3	Evidence of bank erosion	AEDL_5w	B3. Erosion downstream of the crossing, left bank
		5	Evidence of severe bank erosion	AEDR_5w	B4. Erosion downstream of the crossing, right bank
BP_u	C1. Bank protection beneath the crossing	0	No or unsatisfactory photographic evidence	BPL_u	C1a. Bank protection beneath the crossing, left bank	BP_u = max (BPL_u, BPR_u)
		1	Hard structure (concrete/masonry/steel piles)	BPR_u	C1b. Bank protection beneath the crossing, right bank
		3	Soft structure (rip-rap, gabion basket, other)
		5	No protection
BP_5w	C2. Bank protection five channel widths upstream or downstream	0	No or unsatisfactory photographic evidence	BPUL_5w	C2a. Bank protection upstream of the crossing, left bank	BP_5w = max (BPUL_5w, BPUR_5w, BPDL_5w, BPDR_5w)
		1	Hard structure (concrete/masonry/steel piles)	BPUR_5w	C2b. Bank protection upstream of the crossing, right bank
		3	Soft structure (rip-rap, gabion basket, other)	BPDL_5w	C2c. Bank protection downstream of the crossing, left bank
		5	No protection	BPDR_5w	C2d. Bank protection downstream of the crossing, right bank
Condition	Condition of bank protection	1	Undamaged – intact as-new condition
		2	Minor damage – intact but with some isolated damage
		3	Moderate – intact but with widespread damage
		4	Severe damage – intact but likely to fail and remedial work required to stabilise bank
		5	Failed – in pieces, offers no protection
β	D. Bank angle	1	<30°
		3	30–80°
		5	>80°/undercut
V	E. Vegetation	1	Both high and low vegetation
		3	Either low or high vegetation
		5	No vegetation or very sparse cover

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