DamWatch A WEB-BASED SOFTWARE SYSTEM TO MONITOR WATERSHED DAMS IN OKLAHOMA

Transcription

1 DamWatch A WEB-BASED SOFTWARE SYSTEM TO MONITOR WATERSHED DAMS IN OKLAHOMA Authors: Larry W. Caldwell, P.E., Oklahoma Conservation Commission, Stillwater, OK Joe Scannell, President,, USEngineering Solutions Corp., Hartford, CT Abstract: In 2011 and 2012, the Oklahoma NRCS and the Oklahoma Conservation Commission worked with USEngineering Solutions Corporation of Hartford, Connecticut, to implement DamWatch, a system to monitor and store data for 2,100 watershed dams in Oklahoma. This project is being funded by NRCS as a national pilot for a web-based watershed information system. DamWatch is a patented web-based monitoring software system that allows watershed sponsors and NRCS personnel to monitor, in real-time, and respond to potentially destructive flood events. DamWatch gathers and archives real-time rainfall and streamflow data from sources such as the National Oceanic and Atmospheric Administration (NOAA), the National Weather Service (NWS), and the United States Geological Survey (USGS). The system compares rainfall data against established sitespecific thresholds of dam capacity and then alerts predetermined staff of potential spillway flows at specific dams. The DamWatch system employs an automatic messaging system that alerts users through various means such as cellular phones, pagers, fax transmissions, or s. Users can monitor these messages during critical flood events and appropriate staff can be dispatched as needed to those dams for which alerts were issued during a storm event. The DamWatch system also stores site-specific data such as as-built drawings, inspection reports, operation & maintenance agreements, emergency action plans, photos, videos, and watershed benefits data. This data can be accessed via remote means to allow interaction between on-site personnel and specialists in various offices. This paper reviews the implementation and experiences of the DamWatch system pilot in Oklahoma. 1

2 Watershed Program Background: Since 1948, the USDA Natural Resources Conservation Service (NRCS) has assisted project sponsors construct over 11,400 dams in 47 states with assistance from one of the following USDA Watershed Program authorizations: Public Law , Public Law , Pilot Watershed Program, and Resource Conservation and Development. Figure 1: This map shows the locations of the 2,000 watershed projects that contain over 11,400 watershed dams in the United States. The red dots represent the eleven watershed projects authorized by the Flood Control Act of 1944 (Public Law ). The green dots represent the watershed projects authorized by the Watershed Protection and Flood Prevention Act of 1954 (Public Law ). These watershed dams are federally-assisted not federally-owned: they are locallyowned and maintained by project sponsors. The sponsors are generally local conservation districts, special use conservancy districts, or municipalities and usually have easements on private lands to construct, operate and maintain the watershed dams. In almost all cases, sponsors have non-technical personnel in charge of the operation and maintenance of the dams and most of the project sponsors rely on NRCS for technical assistance. 2

3 Oklahoma Watershed Background: Oklahoma has been a national leader in Watershed Program since its inception. Oklahoma has many national watershed firsts including the first watershed dam built in the nation (Cloud Creek Watershed dam no. 1 near Cordell, OK) and the first watershed dam rehabilitated (Sergeant Major Creek Watershed dam no. 2, near Cheyenne, OK). There have been 2,107 watershed dams constructed in Oklahoma since 1948; more than any state in the nation. Typically, the Oklahoma watershed dams are earthen embankments ranging from 20 to 80 feet in height with earthen vegetated spillways and concrete or metal principal spillways. Many times they are located in remote areas. Most of the dams are designed primarily for flood control, grade stabilization, water supply or recreation. Therefore, they typically do not store much water except for short periods following large storm events. Figure 2: Oklahoma has 2,107 watershed dams in 121 watershed projects. Not only does Oklahoma have the most watershed dams in the nation, they also have some of the oldest. By the end of 2012, there will be over 675 watershed dams that have reached the end of end of their 50-year design life: within the next five years over 1,300 watershed dams will reach this milestone. The oldest watershed dam in the state is now 64 years old. Most all of the dams have a 50-year planned evaluated life. 3

4 Critical Watershed Information: Over time, the watershed program has generated a considerable amount of records and data that are invaluable during an emergency caused by a potential structural failure or large rainfall event. Knowing where records are located and accessing them quickly is critical. As-built drawings, the original construction drawings with notes of changes made during construction, are an example of a critical record. Other important documents include operation and maintenance (O&M) inspection reports and agreements that describe O&M needs and commitments made by sponsors and the NRCS. The original project work plans and other program documents also are needed for future reference. Each of the 229 high-hazard watershed dams in Oklahoma has an emergency action plan (EAP) to aid first responders and local emergency managers with site-specific information if the dam should fail. Having access to the current EAP is critical for identifying and evacuating people at-risk downstream from the dam. Having a system that allows storage and retrieval of vital dam records is important because the number of records grows as the dams age and employees and sponsors are not as familiar as to where they are located. From 2006 to 2010, Oklahoma NRCS staff scanned all of the critical watershed records so that they could be stored and accessed electronically. The records included more than 32,000 electronic files; their size exceeded thirteen gigabytes. The issue then became how to make this data available to all who needed access. It was not reasonable to use DVDs or due to the sheer number and size of the data files and the difficulty in keeping them updated. A web-based software system was identified through a market survey as the best way to store and retrieve the dam safety information. DamWatch was the only software meeting the all the system functionality required to store and retrieve critical information about the watershed dams, provide real-time precipitation data and alerts, and the ability to conduct mock emergency events for EAP training. Oklahoma NRCS developed a proposal to pilot the DamWatch system using Oklahoma s electronic data and watershed experience in the state. The proposal was accepted and funding was provided by the NRCS national headquarters to conduct a two-year pilot of the system in Oklahoma. DamWatch Description: DamWatch is a patented web-based dam-monitoring software system that empowers NRCS, project sponsors, and emergency managers to leverage electronically stored dam-safety data with real-time data monitoring. The system is linked with real-time precipitation and stream flow data from the National Weather Service (NWS) and the United States Geological Survey (USGS) to alert identified staff and emergency personnel of predetermined site-specific thresholds. Upon receipt of alerts, personnel can use the system interface (see Figure 3) to determine if preventative actions or emergency response is needed for potentially life-threatening situations, especially those involving high hazard dams. 4

5 Figure 3: Overview of the Oklahoma NRCS User Interface The basic engineering and program data stored in the Oklahoma DamWatch system include the following: As-built construction drawings National inventory of dams (NID) data Emergency action plans Current hazard classification data Breach inundation maps O&M agreements Project benefits Annual inspection reports Assessment reports Watershed project work plans Photos Videos Dam modifications or repairs Auxiliary spillway flow history Other dam safety information DamWatch enables 24/7 real-time access to this information via the web by multiple entities and mobile users as opposed to having access restricted only to those with the ability to get to an office and file cabinet drawers. 5

6 Figure 4: DamWatch's File tab with examples of an as-built and O&M agreement. DamWatch utilizes GIS to display the dam location and drainage area and allows the dam owner and dam safety personnel to proactively monitor dams, in real time, so they can better respond to potentially hazardous and life threatening storm events. This system can be used to collect and process any real-time data at regular intervals. This data can then be compared against predetermined thresholds to alert essential personnel when the dams are experiencing a critical event. Figure 5: NWS NEXRAD Precipitation Data visible through the user interface. 6

7 Rainfall amounts at specific locations can vary significantly when a precipitation event moves through an area with numerous watershed dams. Using NWS radar data, DamWatch can determine which dams have received the heaviest rainfall within their drainage basin and, therefore, have the highest probability of spillway flow. This allows project sponsors and NRCS to prioritize field inspections of the most critical dams first. They are able to save time and money if preventative actions or emergency response is needed, especially for high hazard dams. DamWatch is a secured active/pro-active web-based monitoring system that is accessible anytime and anywhere in the state or the world for a user that has web-access and proper security clearance. The flexibility of secured-remote access allows NRCS, sponsors, emergency managers, and dam safety officials to make informed decisions based on real-time data and dam information from anywhere at any time. Oklahoma NRCS personnel can remotely access DamWatch using any web-enabled device. Six Motorola Xoom tablet computers were selected to test the ability to access DamWatch in the field. The tablets enable personnel to remotely interact with the system to document activities, upload pictures, or view online files. Each tablet has the capability to receive alerts, view online files, take pictures and videos, and even video chat with other active field personnel. Alert Thresholds: The goal of establishing thresholds for DamWatch is to provide timely notice to users of possible or impending auxiliary spillway flows with special attention given to high hazard dams. The storm rainfall amount detected by NexRad is compared to the threshold amount establish for each dam. If the threshold amount is exceeded, a NexRad alert is issued for that dam. The storm rainfall total amount is the estimated accumulated rainfall, continuously updated, since the last one-hour break in precipitation. Storm duration is defined as the time that a radar station detects precipitation somewhere within the coverage area of the 124 mile radius of the loop of the radar. If no precipitation is detected in a loop for greater than one hour, a new storm total and duration is begun The following methodology was used for establishing the thresholds amounts for each of the 2,107 dams in DamWatch. 1. The designed detention storage volume for each dam was determined in watershed inches. The detention storage values in the NRCS National Inventory of Dams (NID) are used unless they were out of reasonable a range or not available. 2. The rainfall on the dam s drainage area needed to produce the runoff to fill the designed detention storage volume was estimated using the project work plan runoff curve number (RCN) or, if a planned RCN is not available, 78 was used is a default value. 7

8 3. Two precipitation threshold levels were established for each dam each has a corresponding message in the alert as appropriate to describe the situation. Level 1 Alert: The threshold rainfall value is the estimated rainfall to produce enough runoff to fill the designed detention storage. Auxiliary spillway flow may be eminent for these dams. Level 2 Alert: The threshold rainfall value is two inches greater than the estimated rainfall to produce enough runoff to fill the designed detention storage. Auxiliary spillway flow should be likely for these dams. 4. For each dam with an alert, the following example shows the information shown displayed in an initial alert message: NID ID: OK0008 Dam Name: Stillwater Creek No. 26 County: Payne Closest Town: Stillwater Distance from closest town: 1 mile Design hazard: L Current hazard: H Level 1 event Time: Wed Jul 14 14:04 CDT 2010 Exceeding Threshold: 7.2 inches Data Source: Twelve Hour (KICT) 5. Threshold values were not defined for low hazard dams that have detention storages less than a 10 year 24 hour frequency rainfall and significant hazard dams that have detention storages less than a 5 year 24 hour frequency rainfall (generally less than 3 inches of detention storage). Many of these dams are full flow grade stabilization structures (GSS); some may have misinterpreted or missing data in the NID. No threshold values or alerts will be issued for these dams until the data is verified. The following are some limitations of this methodology: Multi-purpose dams may have much greater available detention storage than the design detention storage indicates. This is due to the design storage for municipal water supply, recreation, or irrigation may not be fully used which provides additional detention storage at the time of the storm. The methodology does not account for principal spillway discharge during the storm. Most times this will be minimal. Exceptions include designed full flow GSSs or dams with large principal spillway conduits. The methodology does not capture situations where storms occur over several days. A revised methodology needs to be developed to estimate principal spillway discharge during the storm to deduct from estimated runoff value (later enhancement). 8

9 Oklahoma DamWatch Users: To date, 175 users have been issued log-ins and passwords so they can access the system. These users will include the following: One conservation district employee in each of the 61 conservation districts that have watershed dams The NRCS district conservationist for each of the 61 conservation districts that have watershed dams NRCS employees from the state office, area offices, and national office Oklahoma Conservation Commission employees including watershed technicians who assist conservation districts Selected local emergency managers Milestones for Implementation of the Oklahoma DamWatch System: December 17, 2010: Contract signed by Oklahoma NRCS and USEngineering Solutions (USES). Contract period expires December 31, December 21, 2012: NRCS submitted 4 DVDs containing 32,000 electronic files of the following data to USES: as-built drawings; O&M agreements and plans; project work plans; NID data; EAPs; breach inundation maps; shapefiles of watershed project boundaries, drainage basin boundaries for each dam, and conservation district boundaries, project sponsors with O&M responsibility for each dam, watershed benefits data from the POINTS database, and assessment reports. March, 2011: NRCS established a DamWatch user group of 20 people who represented a cross-section of typical users from the following entities: Conservation districts who serve as sponsors of the projects and are responsible for O&M of the dams NRCS state office, technical office, and field office staff who provide technical assistance to sponsors Oklahoma Conservation Commission (OCC) staff who provide sponsors with technical assistance and funding for operation and maintenance The user group tested the system and submitted their recommendations. April, 2011: Methodology for computing thresholds for alerts prepared by NRCS. National Bulletin issued by NRCS to announce the dam monitoring pilot and advise states to begin scanning of watershed documents. April 26, 2011: One-day DamWatch training provided by USES staff for the 20 person user group in Stillwater, Oklahoma. Six tablets issued to selected testers. May, 2011: NRCS resource engineers, NRCS Assistant State Conservationists, selected NRCS state staff, and OCC watershed technicians added as users May 15-18, 2011: Oklahoma DamWatch system was fully operational; demonstrated at the National Watershed Coalition Conference in Oklahoma City 9

10 October, 2011: Shapefiles of 141 breach inundation maps and database of 1,685 potential damage locations with photos of each one submitted to USES. Test of notification feature conducted for all statewide users. December, 2011: Tablets upgraded to Verison 4G January, 2012: Log-ins issued to 130 conservation district and NRCS field office staffs. Two webinar training sessions conducted for all field offices, technical offices, and state-wide users. February, 2012: Oklahoma DamWatch User s Guide developed and distributed February 27, 2012: One-on-one training provided to 75 participants at the Oklahoma Association of Conservation Districts annual meeting in Oklahoma City May, 2012: Webinar conducted with USES and NRCS and OCC state staffs to discuss procedures for issuing tickets July, 2012: EAPs for 210 high hazard dams with new breach inundation maps and updated contact information loaded on DamWatch to replace existing EAPs Summary of Presentations, Exhibits, and Demonstrations Made: Throughout the pilot, the following presentations, exhibits, and demonstrations were provided to interested organizations. In each case, the groups were impressed with the system and were interested in becoming a part of it. February 28, 2011: Oklahoma Association of Conservation Districts Annual Meeting (presentation), Oklahoma City May 15-18, 2011: National Watershed Coalition Conference (presentation and exhibit), Oklahoma City September 25-28, 2011: Association of State Dam Safety Officials Conference (presentation and exhibit), Washington DC February 27, 2012: Oklahoma Association of Conservation Districts Annual Meeting (presentation / demonstrations), Oklahoma City March 14, 2012: GIS Day at the Capital (exhibit / demonstrations), Oklahoma City March 19, 2012: Oklahoma Emergency Management staff (presentation / demonstration), Oklahoma City May 1, 2012: FEMA Region 6 Mitigation Conference (presentation), Denton, Texas August 1, 2012: American Society of Agricultural and Biological Engineers Conference (presentation), Dallas, Texas 10

11 Summary of NexRad Alerts Issued: From May 2011 to May 2012, there were several large rainfall events in Oklahoma. Six of them were large enough to result in NexRad Alerts being issued by DamWatch. However, in 2010 and 2011 Oklahoma experienced extreme heat and drought conditions (more severe than any time on record, including the Dust Bowl days in the 1930 s). Therefore the reservoirs were extremely low and the landscape was very dry, so most of the storms did not result in significant runoff and auxiliary spillway flows did not occur. However, under more normal climatic conditions, spillway flows would have resulted from many of these storms. In April 2012, the percent basin coverage was increased from 33% to 75% to better define actual rainfall measured within the drainage basins. The following are the storms that DamWatch issued NexRad alerts: Storm Max. Rainfall No. of Dams Period (inches) with NexRad Alerts May 19-20, Nov. 6-7, March 20, April 13, April 30, May 6, In each case where the NWS radar detected more rainfall than the established threshold, alerts were sent via cell phone text and/or messages to the users with subscriptions to the dams affected. Field reviews of actual site conditions of the dams with alerts were made by field staff to assure they were functioning as designed. During two storms, there were issues with one of the National Weather Service radar sites (KFDR) that provided erroneous rainfall measurements; this radar site was taken off-line until the NWS can confirm this site will produce more reliable data. During the May 2011 to June 2012 period, the NWS issued 343 flood warning alerts across the state. Many of these were for areas where watershed projects did not exist. While receiving so many warnings was sometimes annoying, it did give an indication of the areas of the state where flooding was possible. Although many users turned off the NWS flood warning subscription so they would not receive them, it did demonstrate that the DamWatch system can provide numerous NWS flood warning notifications consistently. Lessons Learned: 1. DamWatch is a tremendous tool for conservation districts, NRCS, and emergency managers. It increases the efficiency and effectiveness of all who are responsible for the operation of the dams as well as those involved with protecting the public. When alerts are issued, it saves time and money by better utilizing resources during storm events by prioritizing the dams that need attention. 11

12 2. The DamWatch ticket feature allows conservation districts with experienced personnel to capture site knowledge, the little things that make a big difference, prior to the employees retiring so that the information does not retire with them. 3. The DamWatch system provides a one-stop location for all information associated with watershed dams and projects. 4. Computer tablets provide an excellent means of accessing critical information in the field during emergencies as well as uploading real-time photos and videos for technical specialists to review from other locations. This feature is invaluable for providing the ability for staff to collaborate in real-time. 5. In less than five months from signing the contract, the Oklahoma DamWatch system was adapted to the NRCS watershed program, all data was loaded, and the system was operational. 6. The DamWatch system can be implemented in phases. The initial information is the dam names, location and selected design data that is available in the National Inventory of Dams (NID). The project sponsor and NRCS contact information and the digitized boundaries of the dam s drainage basins are needed to utilize the NWS alert features. Additional users and the remainder of the information on the dams and projects (EAPs, breach maps, photos, inspection reports, benefits data, etc.) can be added later as the information is scanned and made available. 7. A consistent naming convention is needed to identify files and link them to specific dams and projects. 8. For smaller drainage areas (less than 10 square miles), 75% coverage of NexRad radar better defines the actual rainfall that occurs on the drainage basin. 9. Including all pages of as-built construction drawings in one electronic file is recommended over one page per file. 10. Scanning of documents at 240 dpi in pdf format provides readable documents with reasonable file sizes. 11. A water budget that considers cumulative rainfall events over multiple days and principal spillway pipe discharge should be studied to modify the threshold alerts. 12. The staff at USEngineering Solutions is very responsive to assist users whenever needed and adjust the system to meet unique requirements. Conclusion: During the 18 months the Oklahoma DamWatch system pilot has been in operation, it has been found to be a tremendous tool to assist local project sponsors, NRCS, and emergency managers to access all critical dam information needed during emergencies as well as normal day-to-day operation of dams. The alert system provides timely information enabling users to quickly respond to dams that have received excessive rainfall and assists with prioritizing resources during large storm events. Regardless where the DamWatch system is discussed or demonstrated, the reaction has been extremely positive and has generated considerable interest, not only in Oklahoma, but nationwide. 12