A skimmer for use in a manhole includes a frame and cladding. The frame includes an adjustable arc having an adjustable overall length and including an arced member, a first side member and a second side member. The arced member has a first end and a second end opposite the first end and defining a curve therebetween. The first side member is slidably adjustable relative to a first end of the arced member and selectively coupled thereto in one of a plurality of predefined first side member positions. The second side member is slidably adjustable relative to a second end of the arced member and selectively couplable thereto in one of a plurality of predefined second side member positions. The cladding covers a substantially entirety of one side of the frame.