Abu Dawud

Benefits and Issues:
This narration is weak in its chain of transmission; however, the authentic hadith is: "Avoid the two acts that bring about curses: one is to relieve oneself on public pathways, and the other is to do so in places where people seek shade." [صحيح مسلم، حديث :269]
From this hadith, it is correctly deduced that it is not permissible to urinate or defecate in any place—including riverbanks—where it would cause harm to other people.

Commentary:

(1)
According to our esteemed researcher, this narration is weak in its chain of transmission. In Sahih Muslim, this hadith is narrated from Abu Hurairah radi Allahu anhu, but in it, the prohibition is mentioned regarding two places, and there is no mention of the riverbank. See (Sahih Muslim, Kitab al-Taharah, Chapter: The Prohibition of Relieving Oneself in Pathways and Shade, Hadith: 269).
In addition, Shaykh al-Albani has declared it hasan. From this hadith, it is correctly deduced that it is not permissible to urinate or defecate in all such places—including the riverbank—where others may be harmed.
For details, see: (al-Irwa’, Hadith: 62)

(2)
By “riverbank” is meant the edge of a river or pond, etc., where people commonly come and go to fetch water or for other purposes.

(3)
By “shade” is meant such shade where people stop to protect themselves from heat and sunlight; relieving oneself there would cause harm to the general public, and they would not be able to benefit from that shade.
If a tree is growing in such a place where people do not generally need to come and go, then relieving oneself in its shade is permissible, as will be mentioned in Hadith: 338, 339.

(3)
By “in the middle of the path” is meant that one should not relieve oneself right in the path, as this would cause harm to passersby.
However, if one moves aside from the path to a place where people do not pass, it is permissible to relieve oneself there.

Lexical Explanation:
«اِتَّقُوْا» means to beware, to avoid.
«لَاعِنَیْنِ» is the dual form of «لَاعِنٌ». It means: avoid these two matters which become a cause of curse. There is also the possibility that by «لَاعِن» is meant the one who is cursed. Just as «صَاحِبُ اللَّبَن» is called «لَابِن» and «صَاحِبُ التَّمر» is called «تَامِر». (This is what is called the doer possessing such-and-such quality.) And there is also an opinion that «لَاعِنٌ» is in the meaning of «مَلْعُوْنٌ».
«اَلَّذِي یَتَخَلّٰی» is the one who relieves himself, i.e., defecates.
«فِي طَرِیْقِ النَّاسِ» means in the pathways commonly used by people. This is one of the causes of curse. And the second, «أَوْفِي ظِلِّھِمْ», is that place and location where people obtain shade, use it for siesta, or use it for sitting down to rest and relax. By this, general shade is not meant, because if it is a shade not needed by people, then there is no objection or harm in relieving oneself there.
«اَلْمَلَاعِنَ» is the plural of «مَلْعَنٌ». The “meem” has a fatha. These are places that become a cause of curse.
«اَلثَّلَاثَةُ» is in the accusative case due to being the attribute of mala‘in.
«اَلْبَرَاز» — the “ba” has a fatha. And baraz originally means an open and wide place, but here it is a euphemism for «اَلْغَائِط», i.e., the waste expelled from the belly through the anus. If «اَلْبَرَاز» is read in the accusative, then in that case it will be a substitute (badal) for «ملاعن», and if it is read in the nominative, then it is the predicate of an omitted subject.
«فِي الْمَوَارِدِ» is the plural of maurid. It refers to the place, spring, or canal, etc., where people go to drink water, give water to animals, or to take water for ablution (wudu), ritual bath (ghusl), etc. (what are called ghats).
«قَارِعَةِ الطَّرِیقِ» refers to such an open pathway where people pass by and trample it with their shoes, feet, and mounts.
«أَوْ نَقْعِ مَاءٍ» — the “nun” has a fatha and the “qaf” is silent. It is a place where water is collected or where water gathers.
«فِیْھِمَا ضَعْفٌ» — by this is meant that both narrations reported from Sayyiduna Mu‘adh and Sayyiduna Ibn ‘Abbas radi Allahu anhum are weak.
◈ The narration reported from Sayyiduna Mu‘adh radi Allahu anhu is weak because Abu Sa‘id Himyari narrates from Sayyiduna Mu‘adh radi Allahu anhu, even though he did not meet him, so this narration is disconnected (munqati‘).
◈ And the narration reported from Sayyiduna Ibn ‘Abbas radi Allahu anhuma is weak for two reasons: one is that in its chain is a narrator, Ibn Lahi‘ah, and when his books were burned, he began to mix up narrations. The second reason is that the narrator who reports from Sayyiduna Ibn ‘Abbas radi Allahu anhuma is ambiguous; his name is not mentioned.
«تَحْتَ الْأَشْجَارِ الْمُثْمِرَةِ» — relieving oneself under fruit-bearing trees. This is prohibited due to the risk that any fruit that ripens and falls down will become contaminated by filth and thus become dirty and unfit for eating or use. Anyone passing by may unknowingly pick it up, or someone passing for some other need may be harmed by this filth.
«ضَفَّةِ النَّھْرِ» — the “dad” has a fatha and the “fa” is emphasized (shadda). It means the edge or bank (of a river, etc.). The reason is the same: people will be harmed and troubled by it.
«بِسَنَدٍ ضَعِیْفٍ» — in its chain is Furat ibn Sa’ib, who is a rejected (matruk) narrator. For this reason, this narration is also weak.

Benefits and Issues:
➊ Other than the narration of Sahih Muslim, the other narrations are weak in their chains, but due to supporting evidence, they reach the level of hasan (acceptable).
➋ These ahadith teach the etiquettes of relieving oneself.
➌ There are five places and locations where relieving oneself is prohibited, and they are: on public pathways, under shady trees, at water sources (ghats), under fruit-bearing trees, and on the banks of flowing rivers. Relieving oneself on a public road is prohibited, but if the road has been abandoned and is no longer a public thoroughfare, then there is leeway.

Hadith Narrator: (Sayyiduna Mu‘adh radi Allahu anhu) He was an Ansari companion, belonging to the tribe of Khazraj, hence called Khazraji. He was among the highly respected and senior jurists (fuqaha) of the noble companions radi Allahu anhum. He participated in the Pledge of ‘Aqabah and the Battle of Badr, etc. The Prophet sallallahu alayhi wa sallam appointed him as the governor (wali) of Yemen, and Sayyiduna ‘Umar radi Allahu anhu appointed him as the governor of Syria after Sayyiduna Abu ‘Ubaydah ibn al-Jarrah radi Allahu anhu. He passed away in the plague of ‘Amwas in 17 AH, and according to one opinion, in 18 AH. At that time, he was 38 years old.