Ahmad reported from Ibn Abbas (rad) that defecation is prohibited also at the place where water collects. [And both the two (i.e. the previous and this Hadiths) have weakness].

وَلِأَحْمَدَ; عَنِ ابْنِ عَبَّاسٍ: { أَوْ نَقْعِ مَاءٍ } وَفِيهِمَا ضَعْف ٌ [1]‏ .‏