Restrictor plates and systems for a catch basin hood are provided. The hood can include a front external surface, a front internal surface and an inlet extending therebetween. The hood inlet can defined by a plurality of surfaces, such as a top surface and a bottom surface oriented so that a height-wise cross-section of a flow channel defined by the hood inlet can be substantially trapezoidal, narrowing from an upstream side towards a downstream side. The restrictor plate can include a curbed inlet defined by a plurality of walls, including a top wall and a bottom wall oriented so that a height-wise cross-section of a curbed flow channel defined by the curbed inlet is substantially trapezoidal, whereby the top and bottom walls of the curbed inlet are disposed against respective top and bottom surfaces of the hood inlet without contacting the hood front external surface when secured thereto.