Water use
Introduction
This page describes the LISFLOOD water use routine, and how it is used. It is strongly advisable that the water use routine is always used, even in flood forecasting mode, as irrigation and other abstractions can be of substantial influence to flow conditions, and also since the water use mode was used during the calibration.
The water use routine is used to include water demand, abstraction, net consumption and return flow from various societial sectors:
- dom: use of water in the public sector, e.g. for domestic use
- liv: use of water for livestock
- ene: use of cooling water for the energy sector in thermal or nuclear power plants
- ind: use of water for the manufacturing industry
- irr: water used for crop irrigation
- ric: water used for paddy-rice irrigation
The module water use can be activated by adding the following line to the ‘lfoptions’ element:
<setoption choice="1" name="wateruse"/>
Water demand, abstraction and consumption
LISFLOOD distinguishes between water demand, water abstraction, water consumption and return flow. Abstractions are typically higher than demands due leakage in the public supply network, transmission and evaporation losses during irrigation water transport. Water consumption per sector is typically lower than water demand per sector, since only a part of the water is actually used (and hence exits the system), while the remaining fraction is returned to the system later on. The difference between water abstraction and water consumption is the water return flow. The consumptive water use is the water removed from available supplies without return to a water resource system. LISFLOOD extracts the water demand volume from groundwater and surface water bodies, the consumptive use leaves the hydrological water cycle, the remainder amount of water is returned to the channels.
PART ONE: SECTORS of water demand and consumption
LISFLOOD distinguisges the following sectors of water consumption:
- dom: use of water in the public sector, e.g. for domestic use
- liv: use of water for livestock
- ene: use of cooling water for the energy sector in thermal or nuclear power plants
- ind: use of water for the manufacturing industry
Water demand files for each sector need to be created, in mm per day per gridcell, so typically:
- dom.nc (mm per timestep per gridcell) for domestic water demand
- liv.nc (mm per timestep per gridcell) for livestock water demand
- ene.nc (mm per timestep per gridcell) for energy-cooling water demand
- ind.nc (mm per timestep per gridcell) for manufacturing industry water demand
Typically, water demands are related to amounts of population, livestock, Gross Domestic Product (GDP), gross value added (GVA). They are typically obtained by downscaling national or regional reported data using with higher resolution land use maps.
Paddy-rice irrigation water demand is simulated as described in the dedicated chapter; this chapter explains the computation of the water demand for crop irrigation.
Public water usage and leakage
Public water demand is the water requirement through the public supply network. The water demand externally estimated in mm/day/gridcell and is read into LISFLOOD. Typically, domestic water demands are obtained by downscaling national reported data with higher resolution population maps.
LISFLOOD takes into account that leakage exist in the public supply network, which is defined in an input map:
<textvar name="LeakageFraction" value="$(PathMaps)/leakage.map">
<comment>
$(PathMaps)/leakage.map
Fraction of leakage of public water supply (0=no leakage, 1=100% leakage)
</comment>
</textvar>
The leakage - typically only available as an average percentage per country - is then used to determine the required water abstraction:
Domestic Water Abstraction = dom.nc * (1 + leakage.map)
The actual water consumption of the domestic sector is much less than the abstraction, and is defined by a fixed coefficient or a map if spatial differences are known:
<textvar name="DomesticConsumptiveUseFraction" value="0.20">
<comment>
Consumptive Use (1-Recycling ratio) for domestic water use (0-1)
Source: EEA (2005) State of Environment
</comment>
</textvar>
So, the actual:
DomesticConsumption = DomesticConsumptiveUseFraction * dom.nc
DomesticReturnFlow = (1 - DomesticConsumptiveUseFraction) * dom.nc
DomesticAbstraction = DomesticDemand * DomesticSavingConstant * DomesticLeakageConstant
where
- DomesticSavingConstant = 1 - WaterSavingFraction; WaterSavingFraction accounts for water saving strategies implemented by the households (and not included in the current use scenario).
- DomesticLeakageConstant = 1/{1-[DomLeakageFr * (1 - DomLeakageReductionFrac)]}. DomLeakageFrac represents the fraction of water lost during transport from the source of the abstraction to the final destination and DomLeakageReductionFrac allows to account for a reduction in leakage compared to the current scenario. WaterSavingFraction, DomesticLeakageFraction, and DomesticLeakageReductionFraction are provided as input data, the baseline value is 0, the maximum value is 1. The value of DomesticAbstraction is decreased by DomesticSavingConstant and increased by DomesticLeakageConstant.
The leakage volume is then computed as follows:
Leakage = (DomesticLeakageConstant - 1) * DomesticDemand * DomesticSavingConstant
The input value LeakageLossFraction allows to compute the leakage volume which is lost because of evaporation:
LeakageEvaporated = Leakage * LeakageLossFraction
Finally, it must be considered that only a fraction of the domestic water demand is consumed by the households. This fraction is the DomesticConsumptiveUseFraction, its value varies between 0 and 1 and it is provided as input data.
The total amount of water which leaves the system (and consequently must be subtracted from the water balance) due to domestic water use is then computed as follows:
DomesticConsumptiveUse = DomesticDemand * DomesticSavingConstant * DomesticConsumptiveUseFraction + LeakageEvaporated
It is here noted that the return flow is given by the difference between the domestic water abstraction and the domestic water consumptive use.
Water usage by the energy sector for cooling
Thermal powerplants generate energy through heating water, turn it into steam which spins a steam turbine which drives an electrical generator. Almost all coal, petroleum, nuclear, geothermal, solar thermal electric, and waste incineration plants, as well as many natural gas power stations are thermal, and they require water for cooling during their processing. LISFLOOD typically reads an ‘ene.nc’ file which determines the water demand for the energy sector in mm/day/pixel. Typically, this map is derived from downscaling national reported data using a map of the thermal power plants.
An “EnergyConsumptiveUseFraction” is used to determine the consumptive water usage of thermal power plants
<textvar name="EnergyConsumptiveUseFraction" value="$(PathMaps)/energyconsumptiveuse.map">
<comment>
# Consumptive Use (1-Recycling ratio) for energy water use (0-1)
</comment>
</textvar>
For small rivers the consumptive use varies between 1:2 and 1:3, so 0.33-0.50 (Source: Torcellini et al. (2003) “Consumptive Use for US Power Production”), while for plants close to large open water bodies values of around 0.025 are valid.
The EnergyAbstraction is assumed equal to the EnergyDemand (i.e. losses are assumed to be 0). So, the actual EnergyConsumptiveUse is:
EnergyConsumptiveUse = EnergyDemand * EnergyConsumptiveUseFraction
It is here noted that the return flow is given by the difference between the water abstraction and the water consumptive use.
Water usage by the manufacturing industry
The manufucaturing industry also required water for their processing, much depending on the actual product that is produced, e.g. the paper industry or the clothing industry. LISFLOOD typically reads an ‘ind.nc’ file which determines the water demand for the industry sector in mm/day/pixel. Typically, this map is derived from downscaling national reported data using maps of land use and/or the specific activities.
The amount of water that needs to be abstracted to comply with the demand of the manufacturing industry (IndustrialAbstraction) is often lower than the actual demand (IndustrialDemand) as part of the water is re-used within the industrial processes. The WaterReUseFraction is provided as inpout data, its value varies between 0 and 1 (for instance, a value of 0.5 indicates that half of the water is re-used, that is, used twice). The IndustrialAbstraction is then computed as follows:
IndustrialAbstraction = IndustrialDemand * (1 - WaterReUseFraction)
An IndustrialConsumptiveUseFraction is used to determine the consumptive water usage of the manufacturing industry. This can either be a fixed value, or a spatial explicit map.
<textvar name="IndustrialConsumptiveUseFraction" value="0.15">
<comment>
Consumptive Use (1-Recycling ratio) for industrial water use (0-1)
</comment>
</textvar>
The IndustrialWaterConsumptiveUse is the computed as follows:
IndustrialWaterConsumptiveUse = IndustrialWaterAbstraction * IndustrialConsumptiveUseFraction
It is here noted that the return flow is given by the difference between the water abstraction and the water consumptive use.
Livestock water usage
Livestock also requires water. LISFLOOD typically reads a ‘liv.nc’ file which determines the water demand for livestock in mm/day/pixel. Mubareka et al. (2013) (http://publications.jrc.ec.europa.eu/repository/handle/JRC79600) estimated the water requirements for the livestock sector. These maps are calculated based on livestock density maps for 2005, normalized by the best available field data at continental scale. Water requirements are calculated for these animal categories: cattle, pigs, poultry and sheep and goats. The cattle category is further disaggregated to calves, heifers, bulls and dairy cows. Using values given in the literature, a relationship using air temperature is inferred for the daily water requirements per livestock category. Daily average temperature maps are used in conjunction with the livestock density maps in order to create a temporal series of water requirements for the livestock sector in Europe.
A “LivestockConsumptiveUseFraction” is used to determine the consumptive water usage of livestock. This can either be a fixed value, or a spatial explicit map.
<textvar name="LivestockConsumptiveUseFraction" value="0.15">
<comment>
Consumptive Use (1-Recycling ratio) for livestock water use (0-1)
</comment>
</textvar>
So, the actual:
LivestockConsumptiveUse = LivestockConsumptiveUseFraction * LivestockDemand
The LivestockAbstraction is assumed equal to the LivestockDemand.
It is here noted that the return flow is given by the difference between the water abstraction and the water consumptive use.
Water usage for crop irrigation
Crop irrigation and paddy-rice irrigation are simulated using seperate model subroutines. The methodology for the modelling of paddy-rice irrigation is described here. This paragraph explains the computation of the water volume required by crop irrigation. The modelling of crop irrigation requires the following keyword in the ‘lfoptions’ element:
<setoption choice="1" name="drainedIrrigation"/>
Crop irrigation water demand is assumed equal to the difference between potential transpiration ($T_{max}$) and actual transpiration ($T_a$). The computation of $T_{max}$ and $T_a$ is described in the chapter Water uptake by roots and transpiration. It is here reminded that $T_a$ is lower than $T_{max}$ because plant trasnpiration decreases with decreasing values of soil moisture. $T_a$ is then compared with the amount of water already available in the soil to compute the amount of water to be supplied by irrigation:
$T_{a,irrig} = \min (T_a, w_1 - w_{wp1})$
where $w_1$ and $w_{wp1}$ are the amount of water available and at wilting point, respectively. Root water uptake depletes the soil moisture of the superficial (1a) and upper (1b) soil layers.
CropIrrigationDemand is then computed by:
CropIrrigationDemand = $( T_{max} - T_{a,irrig} ) \cdot IrrigationMult$
where $IrrigationMult$ is a non-dimensional factor generally larger than 1 having the function to account for the additional amount of water required to prevent salinisation problems.
CropIrrigationAbstraction is larger than CropIrrigationDemand in order to account for the water losses within the irrigation system. These losses are quantified using two non-dimensional factors, namely the IrrigationEfficiency and the ConveyanceEfficiency. Both these factors can vary between 0 and 1, the values are required as input data. For example, IrrigationEfficiency is ~0.90 for drip irrigation, and ~0.75 for sprinkling irrigation; ConveyanceEfficiency is ~0.80 for a common type channel. CropIrrigationAbstraction is the computed as follows:
CropIrrigationAbstraction = (CropIrrigationDemand)/(IrrigationEfficiency * ConveyanceEfficiency)
If the soil is frozen (i.e. the $FrostIndex$ is larger than a selected threshold), CropIrrigationDemand is set to 0.
PART TWO: sources of water abstraction
LISFLOOD can abstract water from groundwater or from surface water (rivers, lakes and or reservoirs), or it is derived from unconventional sources, typically desalination.
The sub-division in these three sources is achieved by creating and using the following maps:
- fracgwused.nc (values between 0 and 1) is FractionGroundwaterUsed
- fracncused.nc (values between 0 and 1) is FractionNONconventionalSourcesUsed
Next, LISFLOOD automatically assumes that the remaining water (1-fracgwused-fracncused) is derived from various sources of surface water. Specifically, DomesticConsumpttiveUse, IndustrialConsumpttiveUse, and LivestockConsumpttiveUse can be supplied by groundwater, non-conventional water sources, and surface water. Water resources allocation is computed as follows:
DomesticAbstractionGW = FractionGroundwaterUsed * DomesticWaterConsumptiveUse
DomesticAbstractionNONconv= FractionNONconventionalSourcesUsed * DomesticWaterConsumptiveUse
DomesticAbstractionSurfaceWater = DomesticWaterConsumptiveUse - DomesticWaterAbstractionGW - DomesticAbstractionNONconv
IndustrialAbstractionGW = FractionGroundwaterUsed * IndustrialConsumptiveUse
IndustrialAbstractionNONconv= FractionNONconventionalSourcesUsed * IndustrialConsumptiveUse
IndustrialAbstractionSurfaceWater = IndustrialConsumptiveUse - IndustrialAbstractionGW - IndustrialbstractionNONconv
LivestockAbstractionGW = FractionGroundwaterUsed * LivestockConsumptiveUse
LivestockAbstractionNONconv= FractionNONconventionalSourcesUsed * LivestockConsumptiveUse
LivestockAbstractionSurfaceWater = LivestockConsumptiveUse - LivestockAbstractionGW - LivestockAbstractionNONconv
EnergyConsumpttiveUse is supplied exclusively by surface water:
EnergyAbstractionSurfaceWater = EnergyConsumptiveUse.
CropIrrigationibstraction is supplied by groundwater and surface water:
CropIrrigationAbstractionGW = FractionGroundwaterUsed * CropIrrigationAbstraction
CropIrrigationAbstractionSurfaceWater = CropIrrigationAbstraction - CropIrrigationAbstractionGW.
RiceIrrSurfWaterAbstr is supplied exclusively by surface water.
Surface water sources for abstraction may consist of lakes, reservoirs, and rivers. The definition of the contribution of each surface water body is explained in the paragraph Surface water abstractions from reservoirs, lakes, and rivers.
Groundwater abstractions
The total amount of water that is required from groundwater resources is:
TotalAbstractionFromGroundWater = DomesticAbstractionGW + IndustrialAbstractionGW + LivestockAbstractionGW + CropIrrigationAbstractionGW
In the current LISFLOOD version, groundwater is abstracted for a 100%, so no addtional losses are accounted for, by which more water would need to be abstracted to meet the demand. Also, in the current LISFLOOD version, no limits are set for groundwater abstraction.
LISFLOOD subtracts groundwater from the Lower Zone (LZ). Groundwater depletion can thus be examined by monitoring the LZ levels between the start and the end of a simulation. Given the intra- and inter-annual fluctuations of LZ, it is advisable to extend the monitoring period to at least a decade.
The total amount of water that is required from groundwater resources is compared to the amount of water that is actually available in the Lower Zone. If the water storage in the lower groundwater zone decreases below the value $LZ_{Threshold}$ [mm], the flow from the lower zone to the nearby rivers (base-flow) stops. When sufficient recharge is added to raise the lower zone levels above the threshold, base-flow starts again. This mimics the behaviour of some river basins in very dry episodes, where aquifers temporarily lose their connection to major rivers and base-flow is reduced. The value $LZ_{Threshold}$ has to be found via calibration. Note that keeping large negative values makes sure that there is always baseflow.
<textvar name="LZThreshold" value="$(PathMaps)/lzthreshold.map">
<comment>
threshold value below which there is no outflow to the channel
</comment>
</textvar>
When groundwater is abstracted for usage, it typically could cause a local dip in the LZ values (~ water table) compared to neigbouring pixels. Therefore, a simple option to mimick groundwaterflow is added to LISFLOOD, which evens out the groundwaterlevels with neighbouring pixels. This option can be switched on using:
<setoption choice="1" name="groundwaterSmooth"/>
Non-Conventional abstractions: desalination
Water obtained through desalination is the most common type of non-conventional water usage. It will likely only be active near coastal zones only, since otherwise transportation costs are too high. The amount of desalinated water usage in LISFLOOD is defined using the factor FractionNONconventionalSourcesUsed. It is assumed that the non-conventional water demand is always available. It is abstracted for a 100%, so no losses are accounted for. The total amount of water supplied by non-conventional sources is:
TotalAbstractionFromNonConventionalSources = DomesticAbstractionNONconv + IndustrialAbstractioNONconv + LivestockAbstractionNONconv
Surface water abstractions
The total amount of water to be abstracted by surface water bodies is:
TotalAbstractionFromSurfaceWater = DomesticAbstractionSurfaceWater + IndustrialAbstractionSurfaceWater + LivestockAbstractionSurfaceWater + EnergyAbstractionSurfaceWater + CropIrrigationAbstractionSurfaceWater + RiceIrrSurfWaterAbstr
Water regions
The TotalAbstractionFromGroundWater, the TotalAbstractionFromNonConventionalSources and the TotalWaterAbstractionFromSurfaceWater are extracted within water regions. These regions are introduced in LISFLOOD due to allow the realistic representation of surface water abstraction in high resolution modelling set-ups. When using a 0.5 degree spatial resolution model, the abstraction of surface water from the local 0.5x0.5 degree pixel is a reasonable representation of the real process. Conversely, when using finer spatial resolutions, the water demand of a pixel could be supplied by another pixel nearby (that is, water demand and water abstraction actually occur in different pixels). The water regions were therefore introduced to solve this problem. Specifically, a water region is the area icluding the locations of water demand and abstraction.
Water regions are generally defined by sub-river-basins within a Country. In order to mimick reality, it is advisable to avoid cross-Country-border abstractions. Whenever information is available, it is strongly recommended to align the water regions with the actual areas managed by water management authorities, such as regional water boards. In Europe, the River Basin Districts, as defined in the Water Framework Directive and subdivided by country, can be used.
Water regions can be activated in LISFLOOD by adding the following line to the ‘lfoptions’ element:
<setoption choice="1" name="wateruseRegion"/>
Surface water abstractions from lakes and reservoirs
Lakes and reservoirs within a water region can supply part of the surface water abstraction. The parameter FractionLakeReservoirWaterUsed defines the fraction of surface water abstraction which should be supplied by lakes and reservoirs. The value of this parameter (between 0 and 1) is provided in input to the model.
LISFLOOD then computes the available water volume in lakes and reservoirs. The available water volume of a lake is defined equal to the 10% of its total volume storage. The available water volume in a reservoir is assumed equal to the minimum between the 1% of its total storage capacity and the 2% of the volume stored in the reservoir at the computational time step. These conditions are imposed to constantly preserve a ‘reasonable’ amount of water in reservoirs and lakes. The total water volume which can be potentially abstracted from reservoirs and lakes is then:
TotalAvailableVolumeLakesReservoirs = AvailableVolumeLakes + AvailableVolumeReservoirs
It is here reminded that all the lakes and reservoirs within the same water region are considered for the computation of the available water volume. Similarly, the water demand is computed by considering the whole water region.
The volume which is actually abstracted from lakes and reservoirs within a water region is then given by:
WaterAbstractedLakesReservoirs = min (TotalAvailableVolumeLakesReservoirs , FractionLakeReservoirWaterUsed * TotalAbstractionFromSurfaceWater)
The quantities below are then subtracted from the lake storage and the reservoir storage:
WaterAbstractedLakes = WaterAbstractedLakesReservoirs/TotalAvailableVolumeLakesReservoirs * AvailableVolumeLakes
WaterAbstractedReservoirs = WaterAbstractedLakesReservoirs/TotalAvailableVolumeLakesReservoirs * AvailableVolumeReservoirs
Surface water abstraction from rivers, and environmental flow
The remaining water abstraction volume is demanded to the rivers. The amount of water that should be extracted from the rivers is computed by:
WaterToBeAbstractedChannels = TotalAbstractionFromSurfaceWater - WaterAbstractedLakesReservoirs
WaterToBeAbstractedChannels is withdrawn from discharge in the river network within the same water region. Moreoever, since the exact locations of abstractions are typically not known, river water abstractions are assumed to be homogeneously distributed within the water region.
River discharge at aech time step $Q_{ch}$ is computed by the routing module.
A minum amount of water must always flow in a river. This value is the environmental flow threshold ($EFlowThreshold$) and it is imposed by the user in the settingsfile:
<textvar name="EFlowThreshold" value="$(PathMaps)/dis_nat_10.map">
<comment>
$(PathMaps)/eflow.map
EFlowThreshold is map with m3/s discharge, e.g. the 10th percentile discharge of the baseline run
</comment>
</textvar>
For Europe e.g. the 10th percentile discharge from a ‘natural’ run for 1990-2016 can be used to define the environmental flow threshold. In order to mimick natural flow conditions, a ‘natural’ run does not include without reservoirs and human water abstractions. LISFLOOD also counts the number of days in which the channel flow is lower than the environmental flow threshold ($EFlowThreshold$) as this piece of information is important for water rousources and ecosystem management.
The water volume which can be potentially abstracted from the river within a water region is then:
AvailableVolumeChannels = $\max((Q_{ch} - EFlowThreshold) \cdot \Delta t , 0) \cdot (1 - WUsePercRemain)$
where $WUsePercRemain$ is the percentage of water which always remains in the channel. This value (between 0 and 1) is defined by the user.
The amount of water extracted from the rivers is:
WaterAbstractedFromChannels = min (AvailableVolumeChannel , WaterToBeAbstractedChannels)
A condition in which WaterAbstractedFromChannels is lower than WaterToBeAbstractedChannels means that the sum of the water abstractions from groundwater, non-convential sources, and surface water is lower than the total water abstraction demand. The amount of water which was requested but could not be supplied is the WaterUseShortage and it is quantified as follows:
WaterUseShortage = WaterToBeAbstractedChannels - WaterToBeAbstractedChannels
In condition of water scarcity, water uses are satisfied according to the following order of importance: domestic, energetic, livestock, industry, and irrigation. The latter sentence implies that when WaterUseShortage $\gt 0$, LISFLOOD reduces the water volume delivered to the irrigated fields. Specifically, the amount WaterUseShortage is subtracted from the total amount of water required from surface water bodies by crops and paddy rice, meaning that the total amount of water effectively supplied to the irrigated fields (IrrigationWater) is:
IrrigationWater = CropIrrigationAbstractionGW + CropIrrigationAbstractionSurfaceWater + RiceIrrSurfWaterAbstr - WaterUseShortage
The value IrrigationWater is then used to compute the water content of the superficial soil layer ($w_{1a}$) and of the upper soil layer ($w_{1b}$).
Specifically, the value IrrigationWater (after convertion in [mm]) is first added to the superficial soil layer, until the water content of this layer ($w_{1a}$) is equal to:
$w_{fill,1a} = \min(w_{crit,1a}, w_{pF3,1a})$
where $w_{crit,1a}$ is the critical amount of moisture below which water uptake is reduced and plants start closing their stomata, and $w_{pF3,1a}$ is the lower boundary of the water content which is rapidly available for root water uptake (pF=1000 hPa).
The remainder amount of water (if any) is then added to the upper soil layer ($w_{1b}$). Finally, the actual transpiration rate ($T_a$) is updated to account for the soil moisture deficit due to the irrigation shortage.
In order to check the conservation of mass within the modelled system, LISFLOOD computes the amount of water consumed by irrigation IrriLossCum (this amount of water exits the system): this value accounts for the irrigation water abstracted from groundwater, the irrigation water effectively abstracted from surface water, the amount of water returned to the system due to leakages and losses (defined by the factors IrrigationEfficiency and ConveyanceEfficiency), the resulting water content of the superficial and upper soil layers.
Important techical note for the adequate definition of the water regions
Water demand and water abstraction are spatially distributed within each water region. In other words, the water resourses (surface water bodies and groundwater) are shared inside the water region in order to meet the cumulative requirements of the water region area. For this reason, it is strongly recommended to include the entire water region(s) in the modelled area. If a portion of the water region is not included in the modelled area, then LISFLOOD cannot adequately compute the water demand and abstraction. In other words, LISFLOOD will not be able to account for sources of water outside of the computational domain (it is important to notice that LISFLOOD will not crush but the results will be affected by this discrepancy). The inclusion of the complete water region in the computational domain becomes compulsory under the specific circumstances of model calibration. Calibrated parameters are optmised for a specific model set up. It is often required to calibrate the parameters of several subcatchments inside a basin. Each calibration subcatchment must include a finite number of water regions (each water region can belong to only one subctatchment). If this condition is met, the calibrated parameters can be correctly optimised. Conversely, when a water region belongs to one or more calibration sub-catchments, the water resources are allocated and abstracted in different quantities when modelling the calibration subcatchment only or the entire basin. Similarly, the option groundwater smooth leads to different geometries of the cone of depression due to groundwater abstraction when modelling the subcatchment only or the entire basin. These two scenarios impede the correct calibration of the model parameters and must be avoided. The user is advised to switch off the groundwater smooth option and to ensure the consistency between water regione and calibration cacthments. The utility waterregions can be used to 1) verify the consistency between calibration catchments and water regions or 2) create a water region map which is consistent with a set of calibration points.
Transient or constant water demand
Water demand can change over time. The option TransientWaterDemandChange allows to activate the use of water demand maps containing different values over time.
<setoption choice="1" name="TransientWaterDemandChange"/>
When TransientWaterDemandChange=1 water demand maps must be provided to LISFLOOD as a NetCDF stack (readNetcdfStack=1). Maps can be provided with any frequency, frequency can be different in time. LISFLOOD will continue using the same water demand map until a new water demand map is available in the NetCDF stack (see figure below). Water demand maps follow the same time convention as all other LISFLOOD maps: maps are stored using the timestamp from the end of the time interval they refer to. When TransientWaterDemandChange=0, the same water demand map is used for all time steps.
Figure: Use of transient water demand maps.
The option useWaterDemandAveYear activates the use of water demand average year, namely a set of water demand maps for one single year that will be cycled for every year in the simulation.
<setoption choice="1" name="useWaterDemandAveYear"/>
When useWaterDemandAveYear=1, water demand maps for one single year must be provided to LISFLOOD as a NetCDF stack (readNetcdfStack=1). Maps can be provided with any frequency, frequency can also change in time. LISFLOOD will continue using the same water demand map until a new water demand map is available in the NetCDF stack. The same year will be cycled in time. This option is frequently used for forecasting, when water demand information are not available.
Note: LISFLOOD cannot switch useWaterDemandAveYear on and off during the same simulation. This means it is not possible to run a continuous simulation using water demand maps for a period and an average water demand year for another period. If an average year must be used together with other water demand maps, it is necessary to create a NetCDF file containing existing water demand information and the necessary number of average years.
Water use output files
The water use routine produces a variety of new output maps and indicators, a number of relevant examples is listed in the following Table:
Table: Output of water use routine.
| file | short description | time | area | unit | long description |
|---|---|---|---|---|---|
| Eflow.nc | eflow breach indicator (1=breached) | day | pixel | 0 or 1 | number of days that eflow threshold is breached |
| eneCo.nc | energy consumptive use | day | pixel | mm | energy consumptive use |
| indCo.nc | industrial consumptive use | day | pixel | mm | industrial consumptive use |
| livCo.nc | livestock consumptive use | day | pixel | mm | livestock consumptive use |
| domCo.nc | domestic consumptive use | day | pixel | mm | domestic consumptive use |
| Fk1.nc | Falkenmark 1 index (local water only) | month | region | m3/capita | water availability per capita (local water only) |
| Fk3.nc | Falkenmark 3 index (external inflow also) | month | region | m3/capita | water availability per capita (local water + external inflow) |
| IrSh.nc | water shortage | month | region | m3 | water shortage due to availability restrictions |
| WDI.nc | Water Dependency Index | month | region | fraction | local water demand that cannot be met by local water / total water demand |
| WeiA.nc | Water Exploitation Index Abstraction | month | region | fraction | water abstraction / (local water + external inflow) |
| WeiC.nc | Water Exploitation Index Consumption WEI+ | month | region | fraction | water consumption / (local water + external inflow) |
| WeiD.nc | Water Exploitation Index Demand WEI | month | region | fraction | water demand / (local water + external inflow) |