# Presentation: 002425

## Climate Forecasts and Reservoir Management : Possibilities and Challenges

**Sankar Arumugam**
**Department of Civil, Construction and Environmental Engineering**
**North Carolina State University, Raleigh **
**&**
**International Research Institute for Climate and Society **
**Columbia University, Palisades**

## Acknowledgements

**IRI, Columbia University, Palisades**
- Upmanu Lall
- Casey Brown
- Neil Ward
**FUNCEME, Ceara, North East Brazil**
- Assis Filho De Souza
**PAGASA, Manila, Philippines**
- Susan Espinuvea

## Large Scale Hydroclimatology & Water Management

**Notes:**
Hydroclimatic information in the form of both SST anomalies and land surface moisture conditions play an important role in determining the streamflow potential of the basin at seasonal/interannual time scale. For instance, climatic information, in the form of anomalous conditions in sea surface temperature over the tropics, alter the continental storm tracks/ precipitation in the form of teleconnection. Similarly, land surface conditions, like snow pack depth and soil moisture storage influence the streamflow potential of the basin at seasonal time scales. So, identification of these dominant hydroclimatic modes and coupling them with appropriate hydrologic model, one could  predict the land surface response, streamflow, well in advance. Such improved prediction at seasonal/interannual l time scale could be exploited  for water management like water allocation and reservoir operation. For instance, ....My primary research interest is in these lines; to understand, model and forecast hydrologic fluxes at large spatial scales and effectively utilize them for water management. In this context, I will present my postdoctoral work carried out IRI, Columbia university that focused in developing short-term water management utilizing seasonal/interannual hydroclimatic prediction.

## TALE OF TWO RIVER BASINS

**Jaguaribe-Metropoilitan**
**HydroSystem, Ceara, Brazil**

**Angat Reservoir, Philippines**

** ****Angat Reservoir  during the 1997-98 El Nino **

## Hydroclimatology of the Basins

_**JMH, Ceara, NE Brazil**_
**Semi-Arid**
**One Rainy season, Rest Zero flows**

_**Angat, Philippines**_
**Humid **
**Two Rainy Seasons (Jun-Sep) & (Oct-Dec)**

**Seasonality of rain determined by N-S migration of the ITCZ**

- JJAS – 30%
- OND – 46%

**3-months lag correlation**
******(Nino3.4,Q****JJAS****) = -0.20**
******(Nino3.4,Q****OND****) = -0.51**

| Predictors | Correlation |
| --- | --- |
| Nino 3.4
Dipole | -0.31
-0.42 |

## Water Management Context

_**JMH, Ceara, NE Brazil**_

_**Angat, Philippines**_

**Priority  Uses**
** ****Municipal **
** ****Industrial**
** ****Agriculture**

**Priority  Uses**
** ****Municipal **
** ****Industrial**
** ****Agriculture**
** ****Hydropower**

**Storage/Annual Demand Ratio: **

**Storage/Annual Demand Ratio:**** **

## Climate Information based Streamflow Forecasts

_**JMH, Ceara, NE Brazil**_
**Predictors: Nino3.4 & Atlantic Dipole**
**Semi-parametric Resampling algorithm**

_**Angat, Philippines**_
**ECHAM 4.5 ONDJF Forecasts in persisted SST mode**
**Parametric Regression**

- (Qpred,Qobs):0.58

- **(Q****obs****,Q****pred****) = 0.75**

## MORAPS (Copyright, IRI)

## Retrospective Analyses on Water Allocation

_**JMH, Ceara, NE Brazil:**_**1990 – 2000;Annual Demand**

## Retrospective Analyses on Water Allocation

_**Angat, Philippines: **_**1987-2001 ONDJF  Allocation**

## Oros - System Losses 

## Angat- Spill Volume (Max Hydro)

## Retrospective Analyses on Water Allocation

_**Angat, Philippines: **_**1987-2001 ONDJF  Allocation**

## Meeting February Target Storage

## Utility of Forecasts As Storage/Demand

**Angat**

**Oros**

**Notes:**
Dem	Stor	Stor/Demand	
365	1940	5.32	
365	1455	3.99	
365	970	2.66	
730	1940	2.66	
730	1455	1.99	
730	970	1.33	
1095	1940	1.77	
1095	1455	1.33	
1095	970	0.89	

## Climate Forecasts – Reservoir Management 

**Forecast is more useful than climatology**
- In reducing System Losses – Spill and Evaporation
- In a system with low Storage/Demand ratio
- In a Seasonal Storage Reservoir than a Over Year System
- In Systems with multiple uses constraining the allocation process

**Notes:**
Angat Storage – 1011 hm3 – Demand :1870 hm3 Storage/Demand: 0.54; Storage/Inflow : 0.015; Residence time of water – 2.2 months
Ceara : 5.42;

## Challenges and Way Forward

**S-I Climate Forecasts Applications for Water Management**
- Integrating Weather Forecasts (0-7 days outlook) with monthly and seasonal climate outlooks
- Adaptive Management with continuous updating of forecasts
- Community Priorities, Restriction and Compensation Mechanisms
- Application involve Risk based management strategies and water supply reliability specification.