An adjustable mold for making drainage channel sections of various sizes, shapes, or slopes, the adjustable mold comprising: an interior mold portion, said interior mold portion defining a base; a base support that interfaces with said base of said interior mold portions; and an exterior mold portion at least partially surrounding said interior mold portion, to thereby define a mold, said exterior mold portion comprising: first and second opposing sidewalls (22, 24) each comprising a distal end and a proximal end, wherein the adjustable mold is structured so that at least said first sidewall is positionable at various distances apart from said second sidewall in order to change the overall width of the drainage channel wherein the first sidewall is hingedly coupled to a first portion of the base support, wherein the second sidewall is hingedly coupled to a second portion of the base support, and wherein the base support is structured such that the first portion of the base support can move relative to the second portion of the base support to allow the first sidewall to be moved towards or away from the second sidewall; first and second opposing endwalls (32, 34), wherein said first endwall is located at the proximal end of said first and second opposing sidewalls (22, 24) and said second endwall is located at the distal end of said first and second opposing sidewalls (22, 24); at least one mold spacer located between said interior mold and at least one of said first and second opposing sidewalls (22, 24) of said exterior mold portion, said mold spacer defining first and second ends (62, 64); and at least one positioning: mechanism structured to allow at least one of said first and second ends (62, 64) of said mold spacer to be positioned at different heights along said at least one of said first and second opposing sidewalls (22, 24) of said exterior mold portion. an interior mold portion, said interior mold portion defining a base; a base support that interfaces with said base of said interior mold portions; and an exterior mold portion at least partially surrounding said interior mold portion, to thereby define a mold, said exterior mold portion comprising: first and second opposing sidewalls (22, 24) each comprising a distal end and a proximal end, wherein the adjustable mold is structured so that at least said first sidewall is positionable at various distances apart from said second sidewall in order to change the overall width of the drainage channel wherein the first sidewall is hingedly coupled to a first portion of the base support, wherein the second sidewall is hingedly coupled to a second portion of the base support, and wherein the base support is structured such that the first portion of the base support can move relative to the second portion of the base support to allow the first sidewall to be moved towards or away from the second sidewall; first and second opposing endwalls (32, 34), wherein said first endwall is located at the proximal end of said first and second opposing sidewalls (22, 24) and said second endwall is located at the distal end of said first and second opposing sidewalls (22, 24); at least one mold spacer located between said interior mold and at least one of said first and second opposing sidewalls (22, 24) of said exterior mold portion, said mold spacer defining first and second ends (62, 64); and at least one positioning: mechanism structured to allow at least one of said first and second ends (62, 64) of said mold spacer to be positioned at different heights along said at least one of said first and second opposing sidewalls (22, 24) of said exterior mold portion. first and second opposing sidewalls (22, 24) each comprising a distal end and a proximal end, wherein the adjustable mold is structured so that at least said first sidewall is positionable at various distances apart from said second sidewall in order to change the overall width of the drainage channel wherein the first sidewall is hingedly coupled to a first portion of the base support, wherein the second sidewall is hingedly coupled to a second portion of the base support, and wherein the base support is structured such that the first portion of the base support can move relative to the second portion of the base support to allow the first sidewall to be moved towards or away from the second sidewall; first and second opposing endwalls (32, 34), wherein said first endwall is located at the proximal end of said first and second opposing sidewalls (22, 24) and said second endwall is located at the distal end of said first and second opposing sidewalls (22, 24); at least one mold spacer located between said interior mold and at least one of said first and second opposing sidewalls (22, 24) of said exterior mold portion, said mold spacer defining first and second ends (62, 64); and at least one positioning: mechanism structured to allow at least one of said first and second ends (62, 64) of said mold spacer to be positioned at different heights along said at least one of said first and second opposing sidewalls (22, 24) of said exterior mold portion.