Gartered Spotted Shovel Head Water Viper

This 4 foot plus long water shallow water swimmer was found in a drainage canal. It had a thick brown spotted body like a water snake, a strip down its back like a garter snake, and A flat trianglar head and striked at me like a viper. It prefered water as it returned after I removed it from the canal. Upon seeing the head and the way it wanted to eat me, I left it alone after that. I am unable to identify this snake. I am located in Southern New Mexico and it does closely resemble a massua rattle snake. Excuse my spelling please.