Can the Hydraulic Push Spell be used in conjunction with Ranged Spellstrike?

Question

Right now im creating a character for a pathfinder game. Suffice to say its a magus with the Eldritch Archer Archetype, which replaces normal Spellstrike with a ranged version:

At 2nd level, whenever an eldritch archer casts a spell that calls for a ranged attack, she can deliver the spell through a ranged weapon she wields as part of a ranged attack. Instead of the free ranged attack normally allowed to deliver the spell, an eldritch archer can make one free ranged attack with a ranged weapon (at her highest base attack bonus) as part of casting this spell. [...]

Hydraulic push is a spell that initiates a Bull Rush. The question is: Can I use hydraulic push in conjunction with ranged spellstrike.

Answer 1

The spell hydraulic push can't be used with ranged spellstrike because the spell doesn't call for a ranged attack

This is a strict, rules-as-written reading; ask the GM if he'll read it differently. The magus archetype eldritch archer's supernatural ability ranged spellstrike says

At 2nd level, whenever an eldritch archer casts a spell that calls for a ranged attack, she can deliver the spell through a ranged weapon she wields as part of a ranged attack. Instead of the free ranged attack normally allowed to deliver the spell, an eldritch archer can make one free ranged attack with a ranged weapon (at her highest base attack bonus) as part of casting this spell. The attack does not increase the spell's range.

Emphasis mine. The spell hydraulic push says

You call forth a quick blast of water that knocks over and soaks one creature or square. You can use this blast of water to make a bull rush against any one creature or object. Your CMB for this bull rush is equal to your caster level plus your Intelligence, Wisdom, or Charisma modifier, whichever is highest. This bull rush does not provoke an attack of opportunity. Hydraulic push extinguishes any normal fires on a creature, object, or in a single 5-foot square which it is targeted against. Magical fires are unaffected.

Emphasis mine. Although a bull rush usually requires an attack roll, the spell hydraulic push itself doesn't call for a ranged attack, making it ineligible for use with the special ability ranged spellstrike.

This means the typical beginning eldritch archer appears to be stuck using spells like mudball, ray of enfeeblement, and snowball—which, in their descriptions, call for ranged touch attacks—with the special ability ranged spellstrike.

As mentioned, this is likely needlessly harsh. Seriously, I can't see a big balance concern with letting an eldritch archer push around and drench a foe with an arrow.

Answer 2

It's a stretch for RAW, but it might pass over as RAI or just a house rule.

The only way for this to work is for one to apply the same reasoning for most Combat Maneuvers replacing melee attacks, to a Magus substituting a Bull Rush for a ranged attack. In other words, in the same way that a Fighter can replace all their attacks with Sunder attempts in an attack action. This answer explores that avenue of approach. This isn't an explicit application of rules; if we're talking about RAW, the train stops shortly at "there is no ranged attack in the spell description," as @HeyICanChan mentions. I won't discuss that because it was obvious to me that a strict RAW approach would not work before I wrote the answer -- plus, it's now already been discussed.

Hydraulic push is a spell that explicitly allows you to "use this blast of water to make a bull rush against any one creature or object" -- you seem to already know this. There isn't anything in the rules that specifically limits the range of a Bull Rush, otherwise polearm-users and Large or larger monsters would have a bad time.

So, a ranged Bull Rush is legit, since the spell specifically allows you to do it and that overrides all general rules. The question is, is a Bull Rush completely interchangeable with an attack by rule definition?

The general ruling for Combat Maneuvers is that:

When performing a combat maneuver, you must use an action appropriate to the maneuver you are attempting to perform. While many combat maneuvers can be performed as part of an attack action, full-attack action, or attack of opportunity (in place of a melee attack), others require a specific action.

Note the phrasing of "in place of the melee attack."

The first sentence of Bull Rush's description reads:

You can make a bull rush as a standard action or as part of a charge, in place of the melee attack.

There are two ways to read this.

1. Bull Rush can either be performed as its own, independent "Bull Rush" standard action, or as a replacement for your melee attack when you Charge.
2. Bull Rush can always be substituted for an attack; that attack is either one provided by a standard action or one provided by a Charge.

Unfortunately, experience leads me to say that 1 is the correct interpretation. Ranged bull rush attempts can be performed RAW (see Trick Shot), no problem; the only issue is that it doesn't replace an attack unless you Charge.

For this to actually work the way you would like, the ranged bull rush which is granted to you as a one-time ability from hydraulic push has to be interchangeable with a ranged attack. It seems clear that it is interchangeable with a melee attack during a charge, specifically, but the rules state that you need your own independent standard action to make a bull rush while not charging. Your DM still might be convinced, if they like the idea or are lenient, but know that it isn't allowed by RAW.