Visión General de Modelos Hidrológicos para Proyectos de Estudios This presentation will touch on some of the items that need to be addressed when performing Projetc Studies for Corps of Engineers Projects. Hydrologic Engineering Center

Objetivos Describir el papel de los modelos hidrológicos en los estudios del Cuerpo de Ingenieros Describir los tipos de estudios en los que generalmente se aplican modelos de cuencas hidrográficas Describir los procedimientos de análisis típicos que incluye el modelado de cuencas hidrográficas Introducir la Cuenca del Punxsutawney Hydrologic Engineering Center

Proceso de escorrentía – Ciclo Hidrológico The hydrologic cycle begins with the evaporation of water from the surface of the ocean. As moist air is lifted, it cools and water vapor condenses to form clouds. Moisture is transported around the globe until it returns to the surface as precipitation. Once the water reaches the ground, one of two processes may occur; 1) some of the water may evaporate back into the atmosphere or 2) the water may penetrate the surface and become groundwater. Groundwater either seeps its way to into the oceans, rivers, and streams, or is released back into the atmosphere through transpiration. The balance of water that remains on the earth's surface is runoff, which empties into lakes, rivers and streams and is carried back to the oceans, where the cycle begins again. Hydrologic Engineering Center

Proceso de escorrentía This is the hydrologic cycle broken into a logical set of steps for inclusion into HEC-HMS Hydrologic Engineering Center

Modelo HEC-HMS de Escorrentía de Cuencas This is the summary of the hydrologic cycle modeled inside HEC-HMS Hydrologic Engineering Center

Estudios del USACE que requieren de modelado de cuencas Estudios de reducción de daños de inundaciones Adecuación del aliviadero para seguridad de la presa Diseño y Operación de Embalses Previsión y alerta de inundaciones Gestión de llanura de inundación Restauración Ambiental (ref. Manual de Aplicaciones del HMS) Types of studies requiring Watershed Modeling Planning and designing new flood-damage reduction facilities. These planning studies are commonly undertaken in response to floods that damage property and threaten public safety. • Operating and/or evaluating existing hydraulic-conveyance and watercontrol facilities. The Corps has responsibility for operation of hundreds of reservoirs nationwide for flood control, water supply, hydropower generation, navigation, and fish and wildlife protection. • Preparing for and responding to floods. Beyond controlling flood waters to reduce damage and protect the public, Corps activities include flood emergency preparedness planning and emergency response. • Regulating floodplain activities. As part of the Corps’ goal to promote wise use of the nation’s floodplains, hydrologic engineers commonly delineate these floodplains to provide information for use regulation. • Restoring or enhancing the environment. The Corps’ environmental mission includes ecosystem restoration, environmental stewardship, and radioactive site cleanup. Each of these activities requires information about the hydrology and hydraulics of sensitive sites so that well-informed decisions can be made. Hydrologic Engineering Center

Los procedimientos habituales de estudio Definir los objetivos del estudio y las necesidades de información Obtener los datos disponibles Elaborar curvas de frecuencia de descarga para las ubicaciones de los medidores Ensamble del modelo hidrológico Desarrollar los parámetros de la cuenca para las ubicaciones de los medidores Regionalizar los parámetros de la cuenca Desarrollar un modelo de cuencas subdividida para satisfacer las necesidades de estudio (con los parámetros regionales) Hydrologic Engineering Center

Los procedimientos habituales de estudio (continuación) Calibrar el modelo con datos medidos Desarrollar hipotéticas tormentas basadas en la frecuencia Calibrar las curvas de frecuencia de descarga de medidores Determinar los hidrogramas de escorrentía y las curvas de frecuencia de descarga en las localizaciones deseadas Aplicar el modelo para determinar las curvas de frecuencia para las condiciones de base y las futuras con el proyecto Hydrologic Engineering Center

Evaluación de de Daños Medidas de Reducción Current guidance for the Corps of Engineers is to apply risk analysis methodologies for determining and analyzing risk reduction studies. This diagram shows the basic steps. For the complete analysis a flow-frequency, stage-flow curve and stage damage curve, all with error, are need to complete the risk analysis. If a levee is one of the risk reduction measures and geotechnical elevation-probability of failure curve should be provided. Hydrologic Engineering Center

Desarrollar las curvas de Frecuencia de Descarga The first step is for the hydrologist or hydrologic engineer to develop a flow-frequency curve. A location(s) is/are selected based on the needs of the study. Sometime you will get lucky and the location of the flow-frequency curve will correspond with a gaging station location and the data from the station can be used to develop a flow-frequency curve. However, and unfortunately, most of the time this is not he case and the curve will need to be developed synthetically. Sometimes there is a gage in the basin that can be used, other times not real data exists and dats from surrounding area must be used. Hydrologic Engineering Center

Determinación de la Frecuencia de Descarga Análisis Estadístico de Datos Medidos If a gage exists at a location of interest, Bulletin 17B procedures can be used to develop a frequency curve. Of course it may be necessary to adjust the data to remove impacts of storage, and other similar impacts, before applying the 17B procedures since they apply to unregulated, homogeneous data. Hydrologic Engineering Center

Determinación de la Frecuencia de Descarga Typically data from other gaging stations in the area can be accessed. It is important that the data used come from a similar meterological region. It would not be prudent to use a gage from a location that receives a lot of rain to estimate the runoff of a desert area. Hydrologic Engineering Center

Determinación de la Frecuencia de Descarga Once data from adjacent stations has been used to develop regional and regression relationships, these can be used in the area of interest. Hydrologic Engineering Center

Desarrollo de Parámetros HMS Additionally the HMS program can be used to develop flow-frequency data at various locations of interest. Hopefully there is a gage in the basin that can be used to calibrate the HMS model. If there is not, then model parameters will have to be estimated from regional regression methods. If there is, then the recorded hydrograph from this gage can be used to calibrate the HMS model. The building of an HMS model may take additional work based on the amount of data available but once the model is built it can then be applied to any risk reduction measures to determine their impacts on flow. Hydrologic Engineering Center

Calibración de Parámetros de la de Cuenca Make adjustments to the HMS parameters, within reason, to calibrate the HMS model. Care should be taken that when adjusting parameters that they are not adjusted out of the range of reality just to make the model reproduce an existing hydrograph. If you have to adjust parameters to unrealistic values than most likely there is something wrong with the HMS model. Either wrong parameters are being used, a method or methods are being used incorre4ctly or, possibly, the model is not physically connected correctly. Hydrologic Engineering Center

Calibración de Parámetros de la de Cuenca Calibration of the model is generally a spiral effort. You will make changes and then rerun the simulation. This will most likely need to be repeated multiple times before the model is behaving correctly. It is also important to use multiple flood events to calibrate the model, if data is available. Hydrologic Engineering Center

Regionalizar los parámetros, subdividir la cuenca y calibrar de nuevo Many times model calibration and parameter development can be accomplished on a more coarse model. Once the model is calibrated it can then be subdivided into smaller pieces, if necessary to fit the view of the actual basin, and recalibrated. Hydrologic Engineering Center

Frecuencias de Flujo de Frecuencias basadas en Tormentas Q Time Runoff Hydrograph 1% Chance Flood Peak Discharge When the model has been calibrated, the flow-frequency curve can be developed using frequency storm method. This method is used to generate flows from the 0.5 event all the way out to the .002 event. If available in the region you are working in, the NOAA 14 update provides rainfall totals all the way to the .001 event. After making the frequency runs, you will have the flows necessary to make a flow-frequency curve. One note of caution is that it is important that the rainfall you are using be reflective of the rainfall over the drainage area above your location of interest. HMS can automatically account for this by using the Analysis Compute method. Hydrologic Engineering Center

Frecuencias de Flujo de Simulaciones Continuas Hydrologic Engineering Center

Resultados de Salidas de Modelos Hidrológicos Curvas de frecuencias de flujo para condiciones del proyecto existentes y futuras Hidrogramas para el análisis del medio ambiente (máximos, mínimos, duraciones) Las entradas para la seguridad de la presa y el enrutamiento del aliviadero Previsión de caudales Hidrogramas de modelo hidráulico del río Hydrologic Engineering Center

Documentos de orientación The Corps of Engineers Headquarters website contains many Engineering Manuals (EM), Engineering Regulations (ER), Engineering Circulars (EC), Engineering Technical Letters (ETL) that provide guidance in many areas relating to studies. The website is http://140.194.76.129/publications/ Hydrologic Engineering Center

Cuenca del Punxsutawney Hydrologic Engineering Center

Cuenca del Punxsutawney Mahoning Creek at Punxsutawney Área de Drenaje = 409 Km2. (158 Sq. Mi.) Hydrologic Engineering Center

Cuenca del Punxsutawney Hydrologic Engineering Center

Talleres para la Cuenca del Punxsutawney Desarrollar un Modelo HEC-HMS Trabajar con Modelos de Precipitación y Pérdidas Calcular Escorrentía Usando Hidrogramas Unitarios Estimar Parámetros UHG desde Eventos Históricos Observados Desarrollar y Aplicar Parámetros de Ruteo Desarrollar un Modelo HEC-HMS Final Subdividido Desarrollar Curvas de Frecuencia de Descarga para Condiciones de Base y Futuras del Proyecto Hydrologic Engineering Center