def get_hydro_node_injections(generators, nodes, dispatch):
    """Get hydro node injections
    
    Parameters
    ----------
    generators : pandas DataFrame
        Generator information
    
    nodes : pandas DataFrame
        Node information
    
    dispatch : pandas DataFrame
        Dispatch at each node
        
    Returns
    -------
    hydro : pandas DataFrame
        Hydro generation at each node
    """
    
    # Hydro generators
    mask_hydro = generators['FUEL_CAT'].isin(['Hydro'])
    generators[mask_hydro]

    # Hydro dispatch at each node
    hydro = (dispatch
             .T
             .join(generators.loc[mask_hydro, 'NODE'], how='left')
             .groupby('NODE').sum()
             .reindex(nodes.index, fill_value=0))
    hydro['level'] = 'hydro'
    
    return hydro