NCECC teaching demonstrator · Synthetic daily simulation

One basin. Nine water bodies.

Follow water through storage, abstractions and irrigation returns. Assess flow and salinity in every river water body with TaqSim and Fishy, then explore water-temperature diagnostics from a linked energy-balance model.

Saved basin evidence · separate dataset

Inspect saved-basin passport

Reopen canonical R1 case · resets method exploration

From water allocation to e-flow assessment

1 · TaqSim

Simulates water and salt moving through storage, users and river water bodies.

2 · Thermal module

Tracks heat with those transfers and demonstrates reservoir and industrial effects.

3 · Fishy

Compares each water body’s physical results with declared flow and salinity criteria.

4 · Ecological interpretation

Needs biological observations, a locally calibrated assessment index, and supporting physical evidence.

Synthetic teaching case: operating rules and assessment thresholds are assumed inputs, not requirements derived by the report methodology. Physical checks do not establish ecological status.

The connected water system

Start with the Inflow / source box to explore water quantity and quality. Click other boxes to follow water through the system; water-body labels open the matching physical inspector, with a link to its criterion assessment. Labels show the selected day’s value for the chosen indicator. On small screens, scroll the network sideways.

65% reservoir branch · 35% bypass

Inflow / sourceSynthetic boundary input Reservoirof 80 million m³ DomesticAgriculture 1Agriculture 2Cooling4 m³/s duty Mixing pointSource → riverDomestic and agricultural returnsAgriculture 2 return: less water, all diverted salt

━ River water bodies   ┄ Return flow carrying salt   Grey branches supply users. Cooling consumes no water; accepted industrial heat is shown in the thermal section.

Follow today's agricultural return water and salt
UserDiverted
m³/s
Consumed / ET
m³/s
Returned
m³/s
Diverted salt
tonnes/day
Returned salt
tonnes/day
Intake → return
mg/L

Inspect every model node

Trace each source, reservoir, river node, water user and terminal. River water bodies also have expandable local e-flow checks. Daily readings follow the selected day; assessment counts cover the full synthetic year.

Selected day

Branch at this nodeValueUnit

Dashed lines are incoming branches (or before cooling); solid lines are outgoing branches (or after cooling). Each curve keeps its own concentration or temperature: quality values are not added together. A gap means no flowing water supports that quality value. Chart scales stay fixed across saved scenarios for this node and variable.

Each arrow is a saved physical branch. Widths compare water flows within this node and day, with a minimum visible width for small flows; scales change with the selection. A dashed arrow is zero or unavailable flow. Orange arrows carry consumption or evaporation out of the river system. Click a neighbouring box to inspect it.

Inspect the accounting · balances, transfers and inventories

Daily balance diagnostics

DiagnosticValueUnit

Incoming branches

BranchFrom → toWater
m³/day
Flow
m³/s
Salt
kg/day
Salt
mg/L
Departure
°C
Arrival
°C
Added heat
MW
Sensible heat
departure → arrival GJ/day

Outgoing branches

BranchFrom → toWater
m³/day
Flow
m³/s
Salt
kg/day
Salt
mg/L
Departure
°C
Arrival
°C
Added heat
MW
Sensible heat
departure → arrival GJ/day

Displayed numbers are rounded; balance diagnostics come from the saved physical accounts rather than subtraction of displayed values. A zero water transfer is zero flow; its concentration and temperature can be undefined (—). Departure and arrival temperatures differ where heat is added on a link. Transfers to the atmosphere use a liquid-water-equivalent sensible-heat temperature, not air or vapour temperature; no salt is carried by evapotranspiration or evaporation.

Initial and end-of-day inventories

Inventory / stateInitialEnd of dayChangeUnit
Inputs and operating context

Physical node-account provenance
Technical details and scenario comparison

Optional supporting material: input series, basin-wide findings, reservoir and thermal diagnostics, assumptions and provenance.

Inputs that drive the simulation

These are the saved synthetic input series. Scenario inflow and irrigation requests apply the selected scenario’s factors. Click any input chart to select the same day throughout the demonstration.

River inflow

Normal inputSelected scenario input

Requested water supply

Agriculture 1Agriculture 2Domestic

Source salt concentration

Concentration entering at the upstream river boundary.

Synthetic open-water evaporation depth

Prescribed mm/day as a seasonal weather proxy, not evaporation calculated from meteorological measurements. The model multiplies this depth by the changing reservoir surface area.

Temperature and industrial heat inputs

Upstream and equilibrium water temperatures

Source waterEffective equilibrium water

Requested industrial heat load

Thermal power the plant asks the river to receive; this is separate from its water-flow requirement.

Input on selected dayValueUnit

Every water body has its own assessment

Today's physical conditions alongside full-year findings. The flow criterion stays fixed across scenarios. Temperature is a physical diagnostic without an ecological pass/fail criterion.

Water bodyFlow today
m³/s
Required today
m³/s
Salt today
mg/L
Temperature today
°C
Flow shortfall
days/year
Salt exceedance
days/year
Dry
days/year

Storage shifts water through time

Follow the reservoir through the selected scenario.

End-of-day storageCapacityOperating reserve

Read this alongside the river assessments

Storage can support users and river flows after the seasonal inflow peak. It can also reduce the water passing downstream earlier in the year. Its releases benefit the regulated branch and mixed river, but cannot restore the upstream bypass.

Every scenario starts with 40 million m³. The reservoir has an 80 million m³ capacity and an 8 million m³ operating reserve. The reserve limits managed releases; evaporation continues below it while water remains. Compare final storage as well as this year's deliveries: a policy that draws down more storage leaves less water for the following year.

A smaller reservoir exposes less water surface

The synthetic area–storage curve is piecewise linear. Surface area is evaluated after inflow and spill, before evaporation and managed release; it therefore differs from an area inferred from the plotted end-of-day storage. Potential evaporation is surface area × prescribed depth. Actual evaporation is capped only by the water available, while the operating reserve limits managed releases.

Surface area used that day

Potential and actual evaporation

PotentialActual
Reservoir evaporation on selected dayValueUnit

How storage and cooling change water temperature

An external energy-balance model follows TaqSim’s daily water transfers. Temperature is a modelled physical condition; no ecological temperature criterion is assigned.

Water + energy accounting

Reservoir inlet, storage and outflow

InletStored waterOutflow

One fully mixed reservoir compartment; no stratification or selective withdrawal. Outflow temperature is volume-weighted across spill and managed release. Spill occurs before surface heat exchange, so combined outflow can differ from the end-of-day stored-water temperature.

River before and after industrial cooling

Before coolingAfter cooling

A gap means no flowing water supports a temperature at that section. No ecological temperature criterion is used.

Accepted and unserved cooling heat

RequestedAccepted by riverUnserved

Explain the mechanism

Inflow mixes with stored water. Atmospheric exchange moves reservoir water toward a supplied effective equilibrium water temperature, which is not an air-temperature series. Exported water carries sensible heat. Surface exchange uses the same storage-dependent surface area as evaporation and includes latent effects once. Releases and return flows transport and mix sensible heat.

Cooling heat is curtailed in proportion to available river flow below the declared design flow. Unserved heat represents curtailed cooling service. This operating rule does not establish an ecological temperature threshold.

Thermal condition on selected dayValueUnit
Thermal provenance and energy checks

Compare the operating choices

Precomputed scenarios, not an optimization. Compare delivery, local environmental findings and storage together. Click a scenario to load it.

ScenarioAgriculture 1
demand supplied
Agriculture 2
demand supplied
Domestic
demand supplied
Final / minimum storage
million m³
Cooling shortfall
days/year
Flow shortfall
water-body days
Salt exceedance
water-body days

A water-body day counts one water body on one day; summed values can exceed 365 and are a screening summary. See individual findings above. Initial storage is 40 million m³ in every scenario; using storage can improve this year's deliveries at a cost to the next year.

Assumptions and provenance

Suggested demonstration sequence
  1. Start with the system overview and click Inflow / source. Choose water flow, salt concentration, salt load and temperature to explain the synthetic boundary inputs.
  2. Follow the source into the upstream water body, reservoir and users. Move to the irrigation season and inspect the bypass after Agriculture 2.
  3. Switch to flow protection, then seasonal protection. Compare the same water body on the same day.
  4. Select the mixed water body before cooling. Explain how irrigation returns restore some flow while returning all diverted salt.
  5. Choose a dry scenario. Inspect all nine assessments, user deliveries and final storage together.
Physical assumptions and synthetic inputs
  • This is a fictional one-year daily teaching example, with seasonal inflow and irrigation demand. It is not a calibrated Zarafshan model.
  • A fixed bifurcation sends 65% of inflow toward the reservoir and 35% down the bypass. Agriculture 2 abstracts from the bypass; domestic supply and Agriculture 1 abstract below the reservoir.
  • Reservoir evaporation equals the synthetic open-water evaporation depth times its storage-dependent surface area, capped by available water. It continues below the managed-release reserve and removes water while leaving salt in storage. Return flows mix with river water before cooling; concentration is calculated from total salt mass divided by total water volume.
  • Cooling consumes no water in this example. Its separate thermal module uses the water run to calculate a curtailed heat discharge and downstream temperature. Wastewater reactions, reservoir stratification and biological responses remain outside this example.
What the assessment does—and what still needs evidence
  • The reference removes users and replaces the reservoir with through-flow, preserving branch geometry. Dry scenarios reduce simulated inflow; the normal unregulated reference and assessment requirements remain fixed.
  • Policy protection levels change operations; they do not redefine the assessment criterion.
  • A dry reach has no defined salt concentration and is never counted as passing quality assessment.
  • Daily means cannot establish subdaily minima. One year cannot support a robust multi-year hydrological-alteration assessment. No biological outcome or official compliance finding is asserted.
Run provenance and balance checks