How would losing episodic memory affect a person's functioning? Episodic memory is defined as the difference between remembering and knowing. Roughly speaking, the criteria for episodic memory is a memory which you remember from a first person vantage point, contains visuals, and is remembered as a specific singular instance. 

What would likely effects be of someone losing the ability to access this type of memory, or to process events into memories in this way?
The best evidence for what you are asking comes from amnesic patients. The most famous and most close to the condition you describe was patient H.M.

See below some extracts from wikipedia :


  Molaison's general condition has been described as heavy anterograde
  amnesia, as well as temporally graded retrograde amnesia (Smith &amp;
  Kosslyn, 2007).Since HM did not show any memory impairment before the
  surgery, the removal of the medial temporal lobes can be held
  responsible for his memory disorder. Consequently, the medial temporal
  lobes can be assumed to be a major component involved in the formation
  of semantic and episodic long-term memories


...


  Despite his amnesic symptoms, Molaison performed quite normally in
  tests of intellectual ability, indicating that some memory functions
  (e.g., short-term stores, stores for words, phonemes, etc.) were not
  impaired by the surgery (Smith &amp; Kosslyn, 2007; Corkin, 2002).
  However, for sentence-level language comprehension and production,
  Molaison exhibited the same deficits and sparing as in memory (MacKay,
  James, Taylor &amp; Marian, 2007).


...


  In addition to his intact working memory and intellectual abilities,
  studies of Molaison's ability to acquire new motor skills demonstrated
  preserved motor learning (Corkin, 2002). In a study conducted by
  Milner in the early 1960s, Molaison acquired the new skill of drawing
  a figure by looking at its reflection in a mirror (Corkin, 2002).


...


  Experiments involving repetition priming underscored Molaison's
  ability to acquire implicit (non-conscious) memories, in contrast to
  his inability to acquire new explicit semantic and episodic memories
  (Corkin, 2002).