  HESS J1825-137 is one of the most powerful and luminous TeV gamma-ray pulsar
wind nebulae (PWNe), making it an excellent laboratory to study particle
transportation around pulsars. We present a model of the (diffusive and
advective) transport and radiative losses of electrons from the pulsar
PSRJ1826-1334 powering HESSJ1825-137 using interstellar medium gas (ISM) data,
soft photon fields and a spatially varying magnetic field. We find that for the
characteristic age of 21 kyr, PSR J1826-1334 is unable to meet the energy
requirements to match the observed X-ray and gamma-ray emission. An older age
of 40 kyr, together with an electron conversion efficiency of 0.14 and
advective flow of $v = 0.002c$, can reproduce the observed multi-wavelengh
emission towards HESS J1825-137. A turbulent ISM with magnetic field of $B =
20\,{\mu}G$ to $60\,{\mu}G$ to the north of HESS J1825-137 (as suggested by ISM
observations) is required to prevent significant gamma-ray contamination
towards the northern TeV source HESS J1826-130.
