National Weather Service United States Department of Commerce

ResSim project


The US Army Corps of Engineers (USACE) Hydrologic Engineering Center (HEC) is the designated Center of Expertise for the US Army Corps of Engineers in the technical areas of surface and groundwater hydrology, river hydraulics and sediment transport, hydrologic statistics and risk analysis, reservoir system analysis, planning analysis, real-time water control management and a number of other closely associated technical subjects. The HEC supports Corps field offices, headquarters, and laboratories by providing technical methods and guidance, water resources models and associated utilities, training and workshops, accomplishing research and development, and performing technical assistance and special projects. HEC models and techniques are widely used by public agencies and by the private sector. One such model is the Reservoir System Simulation program (ResSim). For further information on the USACE HEC visit their website at

The NWS operates thirteen River Forecasts Centers (RFCs) that provide flood and water supply forecasts, guidance, and information for the protection of lives and property and the enhancement of the environment and economy. To accomplish this, the RFCs utilize a suite of software applications called the National Weather Service River Forecast System (NWSRFS). The NWSRFS is a collection of hydrologic models, operations, and data processing functions supported within a well-tested and rigorous operational infrastructure. The NWSRFS was developed by the NOAA/NWS Office of Hydrologic Development (OHD).

The Yuba County Water Agency (YCWA) is leading an interagency effort to develop "Forecast-Coordinated Operations (F-CO)" for Lake Oroville on the Feather River and New Bullards Bar Reservoir on the Yuba River in California. Agencies include the California Department of Water Resources (CADWR), the NWS California-Nevada River Forecast Center (CNRFC), the USACE HEC, and the YCWA. Representatives of these collaborating agencies have agreed to use the HEC’s ResSim model as the centerpiece model for a new decision support system. In order to meet the project requirements, ResSim must be made compatible with the CNRFC operations, who in concert with the CADWR, provide hydrologic forecast and warning support for the Feather and Yuba rivers during routine as well as flood emergency conditions.

Using ResSim within the operations of the CNRFC ensures that all project participants have an identical representation of the river system at all times. To accomplish this, ResSim must be effectively integrated within the CNRFC’s operational system, the NWSRFS. Direct coding of ResSim into NWSRFS is not desirable because expected modifications and updates to ResSim could not be effectively integrated. As such, the YCWA requested, and the OHD agreed, that the OHD would develop a portal from NWSRFS to the most recent version of ResSim available from the USACE using a "service-based" architecture. This is entirely compatible with the OHD's strategy for CHPS.

Through the NWS contract with RSIS, the OHD sub-contracted with Apex Digital Systems in 2006 to analyze, design, and develop a solution for the CNRFC that not only meets the requirements of the F-CO, but will also be "e;CHPS-ready"e;. Since Delft-FEWS is under consideration as an infrastructure solution for CHPS, Apex’s proposed solution centered on a ResSim interface to NWSRFS through the Delft-FEWS. While this makes for a somewhat ‘heavier’ solution with more features than are absolutely necessary for this project, the advantage is that future migration of the CNRFC's ResSim interface to a CHPS environment will be significantly eased.

Having approved this approach, the OHD authorized Apex to begin final implementation for the ResSim project in early April 2007.

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NEWS AND ACTIVITIES (in reverse chronological order)

January 2010

OHD learned in December that changes to the FEWS-ResSim adapter required to handle an updated version of ResSim were not implemented in time for the December SAT. Deltares will make the necessary changes for the January maintenance release.

October 2009

Deltares conducted tests of the HEC-ResSim during SAT on September 21-23; all tests passed. However OHD is waiting for a revised version of HEC's software which correctly handles warm states; formal testing for this version is expected to occur in December. At the present time CNRFC executes HEC-ResSim from NWSRFS; they will be the first RFC to run it within CHPS. Other RFCs are considering implementing HEC-ResSim in the future.

April 2008

The ResSim model was added as a new operation to NWSRFS at CNRFC during 2007. The operation was designed to be "CHPS ready" via the use of FEWS as a "middle man" between NWSRFS and ResSim. Deltares developed the FEWS adapter for ResSim.

CNRFC continued to run the ResSim over the winter with few problems. There was a brief interruption as CNRFC had to make some adjustments after installation of the AWIPS OB8.2 release.

Meanwhile HEC continued to work on the changes needed for a compatible warm start capability. CNRFC‚s upgrade to AWIPS OB8.2 caused a few glitches, but these have now been resolved. Phase 2 (support for ensemble functionality) is just beginning as CNRFC has conducted various requirements gathering sessions with California customers.

January 2008

Acceptance testing at CNRFC occurred during November. An adequately functional version of ResSim was installed, along with OHD's/Apex‚s enhanced version of NWSRFS. An outstanding issue concerning ResSim‚s ability to execute a warm start in the manner expected by RFC forecasters was never resolved. As the necessary changes to ResSim would be extensive, CNRFC agreed that their plan to move forward with ResSim in their operations could proceed with minor impact. The USACE HEC will submit a proposal to the YCWA to make the necessary design and code changes to ResSim. This HEC activity will delay Phase 2, which is expected to add processing of ensemble forecasts in ResSim.

CNRFC will continue to run ResSim over the winter to evaluate its behavior/performance.

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October 2007

During the week of July 9, Delft led an installation at CNRFC bringing all collaborative components together in one place for the first time. This included the Delft-FEWS configured for CNRFC, an early Linux version of the ResSim from HEC, and a modified version of NWSRFS from Apex. The installation revealed some missing functionality needed for NWSRFS, which HSEB provided at short notice, and which was delivered to CNRFC during August.

Full end-to-end testing continued throughout August and early September. Delft sent a hydrologist to CNRFC during the week of September 17 to troubleshoot an outstanding issue on-site. The cause of the problem turned out to be configuration and environment, not software.

For these and other reasons related to CNRFC's anticipated workload, acceptance testing at CNRFC has been delayed until mid-November. A fully functional version of ResSim will be installed at that time, along with an enhanced version of NWSRFS. During the ensuing months CNRFC will run ResSim in parallel with their normal operations.

July 2007

The purpose of this project is to integrate use of the USACE HEC's Reservoir Simulation (ResSim) model into CNRFC operations. The project is a joint effort between the HEC, who is enhancing the ResSim and converting it to Linux, and the NWS who will provide a software interface between ResSim and the NWSRFS. The NWS has specifically designed this interface to be compatible with CHPS; therefore the solution will incorporate the Delft-FEWS as a significant component.

Members of HSEB (Jon Roe, Chris Dietz), Apex, and Delft attended a progress meeting on April 19 in Sacramento, CA for the Yuba-Feather Forecast-Coordinated Operations (F-CO) Management Team. Joan Klipsch, HEC, provided a status report of ResSim development activities; Manuel Mattke (Apex) provided a progress update on NWS activities.

During the past quarter Apex and Delft continued to make good progress. Installation of the NWS solution at CNRFC will occur the week of July 9, with acceptance expected in September.

Following Gary Carter's request for a briefing package suitable for presentation to a wide range of audiences (hydrologists, program managers, upper level management, partners, etc.), Apex developed a package showcasing ResSim as an example of the new business model to be realized through CHPS. Apex completed this briefing by the end of June.

April 2007

The Yuba-Feather Forecast Coordinated Operations (FCO) Management Team has scheduled a progress meeting on April 19 in Sacramento, CA. Manuel Mattke (Apex) will provide a progress update on OHD activities; Jon Roe and Chris Dietz will also attend.

In March HSEB initiated another task with Apex to develop a briefing package suitable for Gary Carter to present to a wide range of audiences, such as: the NWS Corporate Board, the AMS and AGU Conferences, Interagency Committees such as AWCI and SWAQ, HICs and MICs, Congressional Staffers, USGS Meetings, and USACE Meetings. A key point in the briefing package is illustration of the "new way of doing business" being demonstrated concretely with the ResSim project.

January 2007

After a series of meetings and discussions between Apex, Delft, CNRFC, and USACE HEC, Apex presented their technical recommendations to OHD on October 10. This contract task has now been completed; in December HSEB submitted a Statement of Objectives to Contracts for the follow-on work (implementation of the technical recommendations). While this project will integrate ResSim into NWSRFS, it will be designed in such a way as to be "CHPS-ready", so that it will require minimal effort to integrate the solution into the FEWS Pilot after the completion of that project next year.

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October 2006

In the autumn of 2006 OHD received the clear and strong message from the CAT that their approach for CHPS was not going to work for two main reasons:

  1. Simple re-engineering would effectively freeze introduction of new capabilities at River Forecast Centers (RFCs), potentially for several years. One of the original CHPS projects (RRS Preprocessor) was specifically rejected by field representatives at HOSIP Gate 2 for this reason.
  2. The existing software infrastructure of the NWSRFS is so out of date, and requires such a high level of maintenance, that it is no longer cost effective to keep it in service. The bulk of the NWSRFS infrastructure software focuses on a 1970’s era need to streamline computer resources in ways that are now handled by hardware and operating systems. The "core" capabilities of the NWSRFS are a small portion of the entire software package; these capabilities are the only things that must be retained in a CHPS environment.

The CAT’s desire was to consider a completely new infrastructure, not hindered by limitations of the existing NWSRFS design.

On 16 October, 2006 Apex Digital Services hosted a live web-based demonstration of the FEWS for the CAT. The CAT concluded that FEWS has significant potential to become a replacement for NWSRFS, and they requested that OHD develop a demonstration system based on FEWS but functioning in a NWS (RFC) environment.

July 2006

A third CHPS-related external project to provide RFCs access to the USACE Reservoir Simulation (ResSim) model from NWSRFS also made good progress this period. In June OHD awarded a contract to Apex Digital Systems, Inc. to lead this effort. Apex plans to make use of WL | Delft’s FEWS infrastructure as part of its solution. Over the next several months Apex will be working closely with Rob Hartman, HIC at CNRFC, the USACE's Hydrologic Engineering Center (HEC), and consultants from WL | Delft.

April 2006

The external project to provide RFCs access to the USACE Reservoir Simulation (ResSim) model from NWSRFS continued progress this period. Rob Hartman, HIC at CNRFC, is leading the way in engaging OHD and USACE’s Hydrologic Engineering Center (HEC) in a joint project to provide this linkage, funded entirely by the Yuba County California Water Agency (YCWA). All agreements have now been signed, and HSEB is waiting for funding details in order to engage a contractor and begin work. We expect work to begin in early April and USACE-HEC has already begun their tasks.

January 2006

The external project to provide RFCs access to the USACE Reservoir Simulation (ResSim) model from NWSRFS continued progress this period. Rob Hartman, HIC at CNRFC, is leading the way in engaging OHD and USACE’s Hydrologic Engineering Center (HEC) in a joint project to provide this linkage, funded entirely by the Yuba County California Water Agency (YCWA). Rob finalized details of the agreements, and we are now waiting for DoC clearance for NOAA to sign the contract and give OHD the go-ahead to begin work.

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October 2005

The external project to provide RFCs access to the USACE Reservoir Simulation (ResSim) model from NWSRFS continued progress this period. Rob Hartman, HIC at CNRFC, is leading the way in engaging OHD and USACE’s Hydrologic Engineering Center (HEC) in a joint project to provide this linkage, funded entirely by the Yuba County California Water Agency (YCWA). Rob has been working to finalize details of the agreements between all parties and work is now expected to begin in October.

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