Input data

mizuRoute expects 2 or 3 input data depending on how runoff data is provided. If runoff data is provided at each river network HRU (RN_HRU), river network data and runoff data are expected. Otherwise, mizuRoute needs to remap runoff at hydrologic model HRU (HM_HRU) to river network HRU with areal weight averaging. In this case, one additional data, remapping data, is required. All the data need to be stored in netCDF.

Basic netCDF requirement (variable, dimension, etc) are discussed below. Dimension and variable names list mizuRoute default name but can be whatever. If they are not default name, the variable names need to be speficied in control file. Some of variables and dimensions (even if they are the same as default name) have to be specified in control file

River network data

River network netCDF holds river reach-reach topology, reach-hru topology, and river and hru physical parameters. The tables below list minimum requirement. Full list of reach/hru physical parameters possibly included are full list of river and hru physical parameters.

It is recommended that river network topology is built within mizuRoute instead of computing outside, while physically parameters are ideally provided per reach and hru.

Dimensions required

Dimension	Description
seg	river reach
hru	river network catchment or hru (hydrologic response unit)

Minimum variables required

Variable	Dimension	Unit	Type	Description
segId	seg	-	int	unique id of each stream segment
HRUid	hru	-	int	unique hru ID
downSegId	seg	-	int	id of the downstream segment
hruSegId	hru	-	int	id of the stream segment the HRU flows into
area	hru	m2	real	hru area
slope	seg	-	real	slope of segment
length	seg	m	real	length of segment

Negative or zero (<=0) value for downSegId is reserved for no downstream reach, meaning that such reach or hru does not flow into any reach. (i.e., basin outlet). For this reason, segID is required to use positive integer value (>0).

Runoff data

Runoff (total runoff) data can be provided as 1) 2D [time, RN_hru], 2) 2D [time, HM_hru] or 3) 3D [time, i, j].

• Option 1. runoff is given at each river network HRU
• Option 2. runoff is given at each hydrologic model HRU (non-grid)
• Option 3. runoff is given at grid

Dimensions

Option	Dimension	Description
1,2,3	time	time dimension
1	RN_HRU	river network catchment or HRU dimension
2	HM_HRU	hydrologic model catchment or HRU dimension
3	i	x direction dimension
	j	y direction dimension

Variables

Option	Variable	Dimension	Unit	Type	Description
1,2,3	time	time	[time-unit] since yyy-mm-dd 00:00:00	real	time
1	RN_hruID	RN_hru	-	int	river network HRU ID
2	HM_hruID	HM_hru	-	int	hydrologic model HRU ID
1	runoff	time, RN_hru	[length-unit]/[time-unit]	real	total runoff
2		time, HM_hru
3		time, i, j

Attributes: Time variable need at least 2 attributes- units and calendar. Four types of calendar can be handled. These are noleap, standard, gregorian, and proleptic_gregorian. Time unit format is shown in the table.

Runoff mapping data

For runoff input options 2 and 3, runoff mapping data, also in netCDF format, is necessary to compute runoff value for each river network HRU

Option	Dimension	Description
2,3	hru	River network HRU
2,3	data	Vectorized overlapping HRU (or grid boxes)

Required runoff mapping netCDF variables

Option	Variable	Dimension	Unit	type	Descriptions
2,3	RN_hruId	hru	-	int	River network HRU ID
2,3	nOverlaps	hru	-	int	number of overlapping HM_HRUs for each RN_HRU
2,3	weihgt	data	-	real	areal weight of overlapping HM_HRUs
2	HM_hruId	data	-	int	ID of overlapping HM_HRUs
3	i_index	data	-	int	i(x) direction index overlapping grid boxes
	j_index	data	-	int	j(y) direction index overlapping grid boxes

Hope this picture helps you understand mapping netCDF variables.